TJ 4.0 hestitates and surges - follow up x2 to Independent Mechanics
 

'99 TJ 4.0 Auto - within about 3 minutes of a cold start under part
throttle (accelerating reasonably to 45 mph) the engine would start to
stutter, hesitate and surge. water temperature gage shows the mid
mark between cold and 210. when this happens and I open the throttle
wide open it makes good power. on return to part throttle the
hesitate and surge resumes. if i come to a stop while this is going
on then the idle speed dips real low and sometimes stalls. runs very
rough.

if i drive it a few more minutes and get the water temperature all the
way up it seems OK, smooth stable idle, smooth part throttle
acceleration.

in the first vista to the shop, they replaced the MAP sensor because
it showed this code. took the truck back but the problem persisted.

called the shop after this didn't fix the problem. they kept the
truck overnight and tried it cold. didn't happen for them. they
scanned the 'puter and no codes. they put in a set of plugs and
replaced #6 spark plug wire because they said it looked corroded.

told me drive it for a few weeks and call them back. if it fixed the
problem we would discuss how much to pay for the 2nd visit. if it
didn't ...

so i've had the truck back a couple of weeks now and it happens pretty
regularly. took it to Murray's this evening and hooked up a scanner -
no codes, same as the shop with their good equipment and trained techs
....

suggestions?

reboot


---
avast! Antivirus: Outbound message clean.
Virus Database (VPS): 000778-2, 10/03/2007
Tested on: 10/4/2007 12:14:28 AM
avast! - copyright (c) 1988-2007 ALWIL Software.
http://www.avast.com

Re: TJ 4.0 hestitates and surges - follow up x2 to Independent Mechanics
 

Well, if you believe in their equipment and techs, than the problem has
to be in the cheap gasoline with alcohol you're trying to feed it.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

"reboot" <reboot@nothere.com> wrote in message
news:kbp8g3128soho3flau134ni4npegrj2sep@4ax.com...
> '99 TJ 4.0 Auto - within about 3 minutes of a cold start under part
> throttle (accelerating reasonably to 45 mph) the engine would start to
> stutter, hesitate and surge. water temperature gage shows the mid
> mark between cold and 210. when this happens and I open the throttle
> wide open it makes good power. on return to part throttle the
> hesitate and surge resumes. if i come to a stop while this is going
> on then the idle speed dips real low and sometimes stalls. runs very
> rough.
>
> if i drive it a few more minutes and get the water temperature all the
> way up it seems OK, smooth stable idle, smooth part throttle
> acceleration.
>
> in the first vista to the shop, they replaced the MAP sensor because
> it showed this code. took the truck back but the problem persisted.
>
> called the shop after this didn't fix the problem. they kept the
> truck overnight and tried it cold. didn't happen for them. they
> scanned the 'puter and no codes. they put in a set of plugs and
> replaced #6 spark plug wire because they said it looked corroded.
>
> told me drive it for a few weeks and call them back. if it fixed the
> problem we would discuss how much to pay for the 2nd visit. if it
> didn't ...
>
> so i've had the truck back a couple of weeks now and it happens pretty
> regularly. took it to Murray's this evening and hooked up a scanner -
> no codes, same as the shop with their good equipment and trained techs
> ...
>
> suggestions?
>
> reboot
>
>
> ---
> avast! Antivirus: Outbound message clean.
> Virus Database (VPS): 000778-2, 10/03/2007
> Tested on: 10/4/2007 12:14:28 AM
> avast! - copyright (c) 1988-2007 ALWIL Software.
> http://www.avast.com
>
>
>

Re: TJ 4.0 hestitates and surges - follow up x2 to Independent Mechanics
 

Well, if you believe in their equipment and techs, than the problem has
to be in the cheap gasoline with alcohol you're trying to feed it.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

"reboot" <reboot@nothere.com> wrote in message
news:kbp8g3128soho3flau134ni4npegrj2sep@4ax.com...
> '99 TJ 4.0 Auto - within about 3 minutes of a cold start under part
> throttle (accelerating reasonably to 45 mph) the engine would start to
> stutter, hesitate and surge. water temperature gage shows the mid
> mark between cold and 210. when this happens and I open the throttle
> wide open it makes good power. on return to part throttle the
> hesitate and surge resumes. if i come to a stop while this is going
> on then the idle speed dips real low and sometimes stalls. runs very
> rough.
>
> if i drive it a few more minutes and get the water temperature all the
> way up it seems OK, smooth stable idle, smooth part throttle
> acceleration.
>
> in the first vista to the shop, they replaced the MAP sensor because
> it showed this code. took the truck back but the problem persisted.
>
> called the shop after this didn't fix the problem. they kept the
> truck overnight and tried it cold. didn't happen for them. they
> scanned the 'puter and no codes. they put in a set of plugs and
> replaced #6 spark plug wire because they said it looked corroded.
>
> told me drive it for a few weeks and call them back. if it fixed the
> problem we would discuss how much to pay for the 2nd visit. if it
> didn't ...
>
> so i've had the truck back a couple of weeks now and it happens pretty
> regularly. took it to Murray's this evening and hooked up a scanner -
> no codes, same as the shop with their good equipment and trained techs
> ...
>
> suggestions?
>
> reboot
>
>
> ---
> avast! Antivirus: Outbound message clean.
> Virus Database (VPS): 000778-2, 10/03/2007
> Tested on: 10/4/2007 12:14:28 AM
> avast! - copyright (c) 1988-2007 ALWIL Software.
> http://www.avast.com
>
>
>

Re: TJ 4.0 hestitates and surges - follow up x2 to Independent Mechanics
 

Well, if you believe in their equipment and techs, than the problem has
to be in the cheap gasoline with alcohol you're trying to feed it.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

"reboot" <reboot@nothere.com> wrote in message
news:kbp8g3128soho3flau134ni4npegrj2sep@4ax.com...
> '99 TJ 4.0 Auto - within about 3 minutes of a cold start under part
> throttle (accelerating reasonably to 45 mph) the engine would start to
> stutter, hesitate and surge. water temperature gage shows the mid
> mark between cold and 210. when this happens and I open the throttle
> wide open it makes good power. on return to part throttle the
> hesitate and surge resumes. if i come to a stop while this is going
> on then the idle speed dips real low and sometimes stalls. runs very
> rough.
>
> if i drive it a few more minutes and get the water temperature all the
> way up it seems OK, smooth stable idle, smooth part throttle
> acceleration.
>
> in the first vista to the shop, they replaced the MAP sensor because
> it showed this code. took the truck back but the problem persisted.
>
> called the shop after this didn't fix the problem. they kept the
> truck overnight and tried it cold. didn't happen for them. they
> scanned the 'puter and no codes. they put in a set of plugs and
> replaced #6 spark plug wire because they said it looked corroded.
>
> told me drive it for a few weeks and call them back. if it fixed the
> problem we would discuss how much to pay for the 2nd visit. if it
> didn't ...
>
> so i've had the truck back a couple of weeks now and it happens pretty
> regularly. took it to Murray's this evening and hooked up a scanner -
> no codes, same as the shop with their good equipment and trained techs
> ...
>
> suggestions?
>
> reboot
>
>
> ---
> avast! Antivirus: Outbound message clean.
> Virus Database (VPS): 000778-2, 10/03/2007
> Tested on: 10/4/2007 12:14:28 AM
> avast! - copyright (c) 1988-2007 ALWIL Software.
> http://www.avast.com
>
>
>

Re: TJ 4.0 hestitates and surges - follow up x2 to Independent Mechanics
 

Well, if you believe in their equipment and techs, than the problem has
to be in the cheap gasoline with alcohol you're trying to feed it.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/

"reboot" <reboot@nothere.com> wrote in message
news:kbp8g3128soho3flau134ni4npegrj2sep@4ax.com...
> '99 TJ 4.0 Auto - within about 3 minutes of a cold start under part
> throttle (accelerating reasonably to 45 mph) the engine would start to
> stutter, hesitate and surge. water temperature gage shows the mid
> mark between cold and 210. when this happens and I open the throttle
> wide open it makes good power. on return to part throttle the
> hesitate and surge resumes. if i come to a stop while this is going
> on then the idle speed dips real low and sometimes stalls. runs very
> rough.
>
> if i drive it a few more minutes and get the water temperature all the
> way up it seems OK, smooth stable idle, smooth part throttle
> acceleration.
>
> in the first vista to the shop, they replaced the MAP sensor because
> it showed this code. took the truck back but the problem persisted.
>
> called the shop after this didn't fix the problem. they kept the
> truck overnight and tried it cold. didn't happen for them. they
> scanned the 'puter and no codes. they put in a set of plugs and
> replaced #6 spark plug wire because they said it looked corroded.
>
> told me drive it for a few weeks and call them back. if it fixed the
> problem we would discuss how much to pay for the 2nd visit. if it
> didn't ...
>
> so i've had the truck back a couple of weeks now and it happens pretty
> regularly. took it to Murray's this evening and hooked up a scanner -
> no codes, same as the shop with their good equipment and trained techs
> ...
>
> suggestions?
>
> reboot
>
>
> ---
> avast! Antivirus: Outbound message clean.
> Virus Database (VPS): 000778-2, 10/03/2007
> Tested on: 10/4/2007 12:14:28 AM
> avast! - copyright (c) 1988-2007 ALWIL Software.
> http://www.avast.com
>
>
>

Re: TJ 4.0 hestitates and surges - follow up x2 to Independent Mechanics
 

Hey Reboot,
there maybe several reason why any engine hesitates, surges etc.
1) Fuel - weak fuel pump, clogged fuel filter, poor fuel, fuel contaminants
(water usually), stuck choke on carbureted engines, dirty injectors.
Start with the easy fixes first. Fill up at a Brand name gas station
with the recommended Octane gas. Dump a good quality fuel injection/carb
cleaner into the tank. (Amsoil and Redline make an excellent
product). Change fuel filter. Squirt some throttle body/carb cleaner into
the intake. Start it up and squirt some more in working the throttle back
and forth. If you have a pressure gauge you can measure the fuel
pump pressure. If not the boys at the garage can check that for you. Even if
it is in "spec" if it is on the low side, it may need replacement
( I had a Chevy Blazer that had that problem). Also inspect the fuel lines
for kinks and fuel tank for any dents. ( I had a truck with a dented fuel
tank and it could only pick up fuel when it was above the half full
mark).
2) Spark - worn sparkplugs, coil, distributer cap, rotor, wires. Replace
plugs ( I like NGK Iridium's myself), cap and rotor. Looks like you already
had the wires replaced.
If you have a lot of miles on the coil, replace that too. I usually
replace any stock coil with one from Accell or MSD. Gives it a smoother idle
and better throttle response when you go to a higher performance
coil.
3) Air - clogged air filter, dirty throttle body.
Replace air filter. Preferably with one from K and N. The dirty throttle
body was taken care of when you squirted the throttle body cleaner into the
intake.
4) Exhaust - Clogged or defective ERG (Exhaust gas recirculation), kinked or
bent exhaust pipe, clogged catalytic converter. weak or worn O2 sensors.
Inspect exhaust for dents. Replace the O2 sensors (most have 2 - one in
front of the Cat and one behind) if the above steps haven't fixed your
problem.
Replace any kinked exhaust pipes. Remove and clean out your ERG valve.
Your may have to replace it if it is badly worn. I am betting that the ERG
is stuck open and that is why you are getting the majority of your
problems when it is cold. Start with that.

Hope this helps...
Peter@gojeepgo.ca

"reboot" <reboot@nothere.com> wrote in message
news:kbp8g3128soho3flau134ni4npegrj2sep@4ax.com...
> '99 TJ 4.0 Auto - within about 3 minutes of a cold start under part
> throttle (accelerating reasonably to 45 mph) the engine would start to
> stutter, hesitate and surge. water temperature gage shows the mid
> mark between cold and 210. when this happens and I open the throttle
> wide open it makes good power. on return to part throttle the
> hesitate and surge resumes. if i come to a stop while this is going
> on then the idle speed dips real low and sometimes stalls. runs very
> rough.
>
> if i drive it a few more minutes and get the water temperature all the
> way up it seems OK, smooth stable idle, smooth part throttle
> acceleration.
>
> in the first vista to the shop, they replaced the MAP sensor because
> it showed this code. took the truck back but the problem persisted.
>
> called the shop after this didn't fix the problem. they kept the
> truck overnight and tried it cold. didn't happen for them. they
> scanned the 'puter and no codes. they put in a set of plugs and
> replaced #6 spark plug wire because they said it looked corroded.
>
> told me drive it for a few weeks and call them back. if it fixed the
> problem we would discuss how much to pay for the 2nd visit. if it
> didn't ...
>
> so i've had the truck back a couple of weeks now and it happens pretty
> regularly. took it to Murray's this evening and hooked up a scanner -
> no codes, same as the shop with their good equipment and trained techs
> ...
>
> suggestions?
>
> reboot
>
>
> ---
> avast! Antivirus: Outbound message clean.
> Virus Database (VPS): 000778-2, 10/03/2007
> Tested on: 10/4/2007 12:14:28 AM
> avast! - copyright (c) 1988-2007 ALWIL Software.
> http://www.avast.com
>
>
>

Re: TJ 4.0 hestitates and surges - follow up x2 to Independent Mechanics
 

Hey Reboot,
there maybe several reason why any engine hesitates, surges etc.
1) Fuel - weak fuel pump, clogged fuel filter, poor fuel, fuel contaminants
(water usually), stuck choke on carbureted engines, dirty injectors.
Start with the easy fixes first. Fill up at a Brand name gas station
with the recommended Octane gas. Dump a good quality fuel injection/carb
cleaner into the tank. (Amsoil and Redline make an excellent
product). Change fuel filter. Squirt some throttle body/carb cleaner into
the intake. Start it up and squirt some more in working the throttle back
and forth. If you have a pressure gauge you can measure the fuel
pump pressure. If not the boys at the garage can check that for you. Even if
it is in "spec" if it is on the low side, it may need replacement
( I had a Chevy Blazer that had that problem). Also inspect the fuel lines
for kinks and fuel tank for any dents. ( I had a truck with a dented fuel
tank and it could only pick up fuel when it was above the half full
mark).
2) Spark - worn sparkplugs, coil, distributer cap, rotor, wires. Replace
plugs ( I like NGK Iridium's myself), cap and rotor. Looks like you already
had the wires replaced.
If you have a lot of miles on the coil, replace that too. I usually
replace any stock coil with one from Accell or MSD. Gives it a smoother idle
and better throttle response when you go to a higher performance
coil.
3) Air - clogged air filter, dirty throttle body.
Replace air filter. Preferably with one from K and N. The dirty throttle
body was taken care of when you squirted the throttle body cleaner into the
intake.
4) Exhaust - Clogged or defective ERG (Exhaust gas recirculation), kinked or
bent exhaust pipe, clogged catalytic converter. weak or worn O2 sensors.
Inspect exhaust for dents. Replace the O2 sensors (most have 2 - one in
front of the Cat and one behind) if the above steps haven't fixed your
problem.
Replace any kinked exhaust pipes. Remove and clean out your ERG valve.
Your may have to replace it if it is badly worn. I am betting that the ERG
is stuck open and that is why you are getting the majority of your
problems when it is cold. Start with that.

Hope this helps...
Peter@gojeepgo.ca

"reboot" <reboot@nothere.com> wrote in message
news:kbp8g3128soho3flau134ni4npegrj2sep@4ax.com...
> '99 TJ 4.0 Auto - within about 3 minutes of a cold start under part
> throttle (accelerating reasonably to 45 mph) the engine would start to
> stutter, hesitate and surge. water temperature gage shows the mid
> mark between cold and 210. when this happens and I open the throttle
> wide open it makes good power. on return to part throttle the
> hesitate and surge resumes. if i come to a stop while this is going
> on then the idle speed dips real low and sometimes stalls. runs very
> rough.
>
> if i drive it a few more minutes and get the water temperature all the
> way up it seems OK, smooth stable idle, smooth part throttle
> acceleration.
>
> in the first vista to the shop, they replaced the MAP sensor because
> it showed this code. took the truck back but the problem persisted.
>
> called the shop after this didn't fix the problem. they kept the
> truck overnight and tried it cold. didn't happen for them. they
> scanned the 'puter and no codes. they put in a set of plugs and
> replaced #6 spark plug wire because they said it looked corroded.
>
> told me drive it for a few weeks and call them back. if it fixed the
> problem we would discuss how much to pay for the 2nd visit. if it
> didn't ...
>
> so i've had the truck back a couple of weeks now and it happens pretty
> regularly. took it to Murray's this evening and hooked up a scanner -
> no codes, same as the shop with their good equipment and trained techs
> ...
>
> suggestions?
>
> reboot
>
>
> ---
> avast! Antivirus: Outbound message clean.
> Virus Database (VPS): 000778-2, 10/03/2007
> Tested on: 10/4/2007 12:14:28 AM
> avast! - copyright (c) 1988-2007 ALWIL Software.
> http://www.avast.com
>
>
>

Re: TJ 4.0 hestitates and surges - follow up x2 to Independent Mechanics
 

Hey Reboot,
there maybe several reason why any engine hesitates, surges etc.
1) Fuel - weak fuel pump, clogged fuel filter, poor fuel, fuel contaminants
(water usually), stuck choke on carbureted engines, dirty injectors.
Start with the easy fixes first. Fill up at a Brand name gas station
with the recommended Octane gas. Dump a good quality fuel injection/carb
cleaner into the tank. (Amsoil and Redline make an excellent
product). Change fuel filter. Squirt some throttle body/carb cleaner into
the intake. Start it up and squirt some more in working the throttle back
and forth. If you have a pressure gauge you can measure the fuel
pump pressure. If not the boys at the garage can check that for you. Even if
it is in "spec" if it is on the low side, it may need replacement
( I had a Chevy Blazer that had that problem). Also inspect the fuel lines
for kinks and fuel tank for any dents. ( I had a truck with a dented fuel
tank and it could only pick up fuel when it was above the half full
mark).
2) Spark - worn sparkplugs, coil, distributer cap, rotor, wires. Replace
plugs ( I like NGK Iridium's myself), cap and rotor. Looks like you already
had the wires replaced.
If you have a lot of miles on the coil, replace that too. I usually
replace any stock coil with one from Accell or MSD. Gives it a smoother idle
and better throttle response when you go to a higher performance
coil.
3) Air - clogged air filter, dirty throttle body.
Replace air filter. Preferably with one from K and N. The dirty throttle
body was taken care of when you squirted the throttle body cleaner into the
intake.
4) Exhaust - Clogged or defective ERG (Exhaust gas recirculation), kinked or
bent exhaust pipe, clogged catalytic converter. weak or worn O2 sensors.
Inspect exhaust for dents. Replace the O2 sensors (most have 2 - one in
front of the Cat and one behind) if the above steps haven't fixed your
problem.
Replace any kinked exhaust pipes. Remove and clean out your ERG valve.
Your may have to replace it if it is badly worn. I am betting that the ERG
is stuck open and that is why you are getting the majority of your
problems when it is cold. Start with that.

Hope this helps...
Peter@gojeepgo.ca

"reboot" <reboot@nothere.com> wrote in message
news:kbp8g3128soho3flau134ni4npegrj2sep@4ax.com...
> '99 TJ 4.0 Auto - within about 3 minutes of a cold start under part
> throttle (accelerating reasonably to 45 mph) the engine would start to
> stutter, hesitate and surge. water temperature gage shows the mid
> mark between cold and 210. when this happens and I open the throttle
> wide open it makes good power. on return to part throttle the
> hesitate and surge resumes. if i come to a stop while this is going
> on then the idle speed dips real low and sometimes stalls. runs very
> rough.
>
> if i drive it a few more minutes and get the water temperature all the
> way up it seems OK, smooth stable idle, smooth part throttle
> acceleration.
>
> in the first vista to the shop, they replaced the MAP sensor because
> it showed this code. took the truck back but the problem persisted.
>
> called the shop after this didn't fix the problem. they kept the
> truck overnight and tried it cold. didn't happen for them. they
> scanned the 'puter and no codes. they put in a set of plugs and
> replaced #6 spark plug wire because they said it looked corroded.
>
> told me drive it for a few weeks and call them back. if it fixed the
> problem we would discuss how much to pay for the 2nd visit. if it
> didn't ...
>
> so i've had the truck back a couple of weeks now and it happens pretty
> regularly. took it to Murray's this evening and hooked up a scanner -
> no codes, same as the shop with their good equipment and trained techs
> ...
>
> suggestions?
>
> reboot
>
>
> ---
> avast! Antivirus: Outbound message clean.
> Virus Database (VPS): 000778-2, 10/03/2007
> Tested on: 10/4/2007 12:14:28 AM
> avast! - copyright (c) 1988-2007 ALWIL Software.
> http://www.avast.com
>
>
>

Re: TJ 4.0 hestitates and surges - follow up x2 to Independent Mechanics
 

Hey Reboot,
there maybe several reason why any engine hesitates, surges etc.
1) Fuel - weak fuel pump, clogged fuel filter, poor fuel, fuel contaminants
(water usually), stuck choke on carbureted engines, dirty injectors.
Start with the easy fixes first. Fill up at a Brand name gas station
with the recommended Octane gas. Dump a good quality fuel injection/carb
cleaner into the tank. (Amsoil and Redline make an excellent
product). Change fuel filter. Squirt some throttle body/carb cleaner into
the intake. Start it up and squirt some more in working the throttle back
and forth. If you have a pressure gauge you can measure the fuel
pump pressure. If not the boys at the garage can check that for you. Even if
it is in "spec" if it is on the low side, it may need replacement
( I had a Chevy Blazer that had that problem). Also inspect the fuel lines
for kinks and fuel tank for any dents. ( I had a truck with a dented fuel
tank and it could only pick up fuel when it was above the half full
mark).
2) Spark - worn sparkplugs, coil, distributer cap, rotor, wires. Replace
plugs ( I like NGK Iridium's myself), cap and rotor. Looks like you already
had the wires replaced.
If you have a lot of miles on the coil, replace that too. I usually
replace any stock coil with one from Accell or MSD. Gives it a smoother idle
and better throttle response when you go to a higher performance
coil.
3) Air - clogged air filter, dirty throttle body.
Replace air filter. Preferably with one from K and N. The dirty throttle
body was taken care of when you squirted the throttle body cleaner into the
intake.
4) Exhaust - Clogged or defective ERG (Exhaust gas recirculation), kinked or
bent exhaust pipe, clogged catalytic converter. weak or worn O2 sensors.
Inspect exhaust for dents. Replace the O2 sensors (most have 2 - one in
front of the Cat and one behind) if the above steps haven't fixed your
problem.
Replace any kinked exhaust pipes. Remove and clean out your ERG valve.
Your may have to replace it if it is badly worn. I am betting that the ERG
is stuck open and that is why you are getting the majority of your
problems when it is cold. Start with that.

Hope this helps...
Peter@gojeepgo.ca

"reboot" <reboot@nothere.com> wrote in message
news:kbp8g3128soho3flau134ni4npegrj2sep@4ax.com...
> '99 TJ 4.0 Auto - within about 3 minutes of a cold start under part
> throttle (accelerating reasonably to 45 mph) the engine would start to
> stutter, hesitate and surge. water temperature gage shows the mid
> mark between cold and 210. when this happens and I open the throttle
> wide open it makes good power. on return to part throttle the
> hesitate and surge resumes. if i come to a stop while this is going
> on then the idle speed dips real low and sometimes stalls. runs very
> rough.
>
> if i drive it a few more minutes and get the water temperature all the
> way up it seems OK, smooth stable idle, smooth part throttle
> acceleration.
>
> in the first vista to the shop, they replaced the MAP sensor because
> it showed this code. took the truck back but the problem persisted.
>
> called the shop after this didn't fix the problem. they kept the
> truck overnight and tried it cold. didn't happen for them. they
> scanned the 'puter and no codes. they put in a set of plugs and
> replaced #6 spark plug wire because they said it looked corroded.
>
> told me drive it for a few weeks and call them back. if it fixed the
> problem we would discuss how much to pay for the 2nd visit. if it
> didn't ...
>
> so i've had the truck back a couple of weeks now and it happens pretty
> regularly. took it to Murray's this evening and hooked up a scanner -
> no codes, same as the shop with their good equipment and trained techs
> ...
>
> suggestions?
>
> reboot
>
>
> ---
> avast! Antivirus: Outbound message clean.
> Virus Database (VPS): 000778-2, 10/03/2007
> Tested on: 10/4/2007 12:14:28 AM
> avast! - copyright (c) 1988-2007 ALWIL Software.
> http://www.avast.com
>
>
>

Re: TJ 4.0 hestitates and surges - follow up x2 to Independent Mechanics
 

I would first suspect the connection on the TPS needs a clean just
because it is a really common failure point that is heat sensitive and
controls the shift points as well as the idle speed.

A good spray electronic contact cleaner is best, but even WD40 (Water
Displacement spray) will work, just not last as long.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

reboot wrote:
> '99 TJ 4.0 Auto - within about 3 minutes of a cold start under part
> throttle (accelerating reasonably to 45 mph) the engine would start to
> stutter, hesitate and surge. water temperature gage shows the mid
> mark between cold and 210. when this happens and I open the throttle
> wide open it makes good power. on return to part throttle the
> hesitate and surge resumes. if i come to a stop while this is going
> on then the idle speed dips real low and sometimes stalls. runs very
> rough.
>
> if i drive it a few more minutes and get the water temperature all the
> way up it seems OK, smooth stable idle, smooth part throttle
> acceleration.
>
> in the first vista to the shop, they replaced the MAP sensor because
> it showed this code. took the truck back but the problem persisted.
>
> called the shop after this didn't fix the problem. they kept the
> truck overnight and tried it cold. didn't happen for them. they
> scanned the 'puter and no codes. they put in a set of plugs and
> replaced #6 spark plug wire because they said it looked corroded.
>
> told me drive it for a few weeks and call them back. if it fixed the
> problem we would discuss how much to pay for the 2nd visit. if it
> didn't ...
>
> so i've had the truck back a couple of weeks now and it happens pretty
> regularly. took it to Murray's this evening and hooked up a scanner -
> no codes, same as the shop with their good equipment and trained techs
> ...
>
> suggestions?
>
> reboot
>
>
> ---
> avast! Antivirus: Outbound message clean.
> Virus Database (VPS): 000778-2, 10/03/2007
> Tested on: 10/4/2007 12:14:28 AM
> avast! - copyright (c) 1988-2007 ALWIL Software.
> http://www.avast.com
>
>
>