Missing at idle
 

On my 2000 TJ, I have a miss or rough idle problem. Cleaned the
throttle body out and have newer spark plugs.

What else could be the cause of this?

Thoughts?

Thanks,

Tom

Re: Missing at idle
 

tk wrote:
> On my 2000 TJ, I have a miss or rough idle problem. Cleaned the
> throttle body out and have newer spark plugs.
>
> What else could be the cause of this?
>
> Thoughts?

Have you any PCM codes? If it is electrical, plug wires (if present),
low compression or a bad injector can be the cause.

Re: Missing at idle
 

tk wrote:
> On my 2000 TJ, I have a miss or rough idle problem. Cleaned the
> throttle body out and have newer spark plugs.
>
> What else could be the cause of this?
>
> Thoughts?

Have you any PCM codes? If it is electrical, plug wires (if present),
low compression or a bad injector can be the cause.

Re: Missing at idle
 

tk wrote:
> On my 2000 TJ, I have a miss or rough idle problem. Cleaned the
> throttle body out and have newer spark plugs.
>
> What else could be the cause of this?
>
> Thoughts?

Have you any PCM codes? If it is electrical, plug wires (if present),
low compression or a bad injector can be the cause.

Re: Missing at idle
 

tk wrote:
> On my 2000 TJ, I have a miss or rough idle problem. Cleaned the
> throttle body out and have newer spark plugs.
>
> What else could be the cause of this?
>
> Thoughts?

Have you any PCM codes? If it is electrical, plug wires (if present),
low compression or a bad injector can be the cause.

Re: Missing at idle
 

More information:

Newer 4.0 liter engine

I just replaced the engine about a month ago with a used one with
40000 miles, the mechanic used all of my components (intake/exhaust/
drive accesories) from my old engine that had a cracked head and
bearing failure. The jeep has 95000 on the odometer and idled fine
before the replacement. I have all of the extra parts from the used
engine, I could swap to the injectors with 40K on them or change the
O2 sensor or any other sensor on the intake?

The check engine light came on last night (second time) and then went
out after I tried to get the codes (which I have never got after
numerous tries) with the on-off-on-off-on thing with the key cylinder.
Are you supposed to turn the key all the way to off when doing this?
The key cylinder is (1) off, (2) position 1, (3) on and then (4)
start. Do you go from 1-2-3 back to 1?

I had also had it in to the dealer (stealer) here because I thought
they would be able to get the codes and have a better idea. They
recommended that I change the plugs ($150) and have the fuel system
cleaned ($210), however then were unable to get any stored codes from
the OBC and said none were stored. Probably the most worthless $90
diagnostic cost that I have ever spent.

The plugs are Champion truck plugs with less than 2000 miles on them
and I regapped them to .035 and spayed and wiped out the throttle
body.

Thoughts? Man I hate to take it back to the dealer for another $90 to
tell me nothing especially after spending $1500 on the new motor and
another $600 to have the rear differential bearings replaced.

Re: Missing at idle
 

More information:

Newer 4.0 liter engine

I just replaced the engine about a month ago with a used one with
40000 miles, the mechanic used all of my components (intake/exhaust/
drive accesories) from my old engine that had a cracked head and
bearing failure. The jeep has 95000 on the odometer and idled fine
before the replacement. I have all of the extra parts from the used
engine, I could swap to the injectors with 40K on them or change the
O2 sensor or any other sensor on the intake?

The check engine light came on last night (second time) and then went
out after I tried to get the codes (which I have never got after
numerous tries) with the on-off-on-off-on thing with the key cylinder.
Are you supposed to turn the key all the way to off when doing this?
The key cylinder is (1) off, (2) position 1, (3) on and then (4)
start. Do you go from 1-2-3 back to 1?

I had also had it in to the dealer (stealer) here because I thought
they would be able to get the codes and have a better idea. They
recommended that I change the plugs ($150) and have the fuel system
cleaned ($210), however then were unable to get any stored codes from
the OBC and said none were stored. Probably the most worthless $90
diagnostic cost that I have ever spent.

The plugs are Champion truck plugs with less than 2000 miles on them
and I regapped them to .035 and spayed and wiped out the throttle
body.

Thoughts? Man I hate to take it back to the dealer for another $90 to
tell me nothing especially after spending $1500 on the new motor and
another $600 to have the rear differential bearings replaced.

Re: Missing at idle
 

More information:

Newer 4.0 liter engine

I just replaced the engine about a month ago with a used one with
40000 miles, the mechanic used all of my components (intake/exhaust/
drive accesories) from my old engine that had a cracked head and
bearing failure. The jeep has 95000 on the odometer and idled fine
before the replacement. I have all of the extra parts from the used
engine, I could swap to the injectors with 40K on them or change the
O2 sensor or any other sensor on the intake?

The check engine light came on last night (second time) and then went
out after I tried to get the codes (which I have never got after
numerous tries) with the on-off-on-off-on thing with the key cylinder.
Are you supposed to turn the key all the way to off when doing this?
The key cylinder is (1) off, (2) position 1, (3) on and then (4)
start. Do you go from 1-2-3 back to 1?

I had also had it in to the dealer (stealer) here because I thought
they would be able to get the codes and have a better idea. They
recommended that I change the plugs ($150) and have the fuel system
cleaned ($210), however then were unable to get any stored codes from
the OBC and said none were stored. Probably the most worthless $90
diagnostic cost that I have ever spent.

The plugs are Champion truck plugs with less than 2000 miles on them
and I regapped them to .035 and spayed and wiped out the throttle
body.

Thoughts? Man I hate to take it back to the dealer for another $90 to
tell me nothing especially after spending $1500 on the new motor and
another $600 to have the rear differential bearings replaced.

Re: Missing at idle
 

More information:

Newer 4.0 liter engine

I just replaced the engine about a month ago with a used one with
40000 miles, the mechanic used all of my components (intake/exhaust/
drive accesories) from my old engine that had a cracked head and
bearing failure. The jeep has 95000 on the odometer and idled fine
before the replacement. I have all of the extra parts from the used
engine, I could swap to the injectors with 40K on them or change the
O2 sensor or any other sensor on the intake?

The check engine light came on last night (second time) and then went
out after I tried to get the codes (which I have never got after
numerous tries) with the on-off-on-off-on thing with the key cylinder.
Are you supposed to turn the key all the way to off when doing this?
The key cylinder is (1) off, (2) position 1, (3) on and then (4)
start. Do you go from 1-2-3 back to 1?

I had also had it in to the dealer (stealer) here because I thought
they would be able to get the codes and have a better idea. They
recommended that I change the plugs ($150) and have the fuel system
cleaned ($210), however then were unable to get any stored codes from
the OBC and said none were stored. Probably the most worthless $90
diagnostic cost that I have ever spent.

The plugs are Champion truck plugs with less than 2000 miles on them
and I regapped them to .035 and spayed and wiped out the throttle
body.

Thoughts? Man I hate to take it back to the dealer for another $90 to
tell me nothing especially after spending $1500 on the new motor and
another $600 to have the rear differential bearings replaced.

Re: Missing at idle
 

tk wrote:

> The check engine light came on last night (second time) and then went
> out after I tried to get the codes (which I have never got after
> numerous tries) with the on-off-on-off-on thing with the key cylinder.
> Are you supposed to turn the key all the way to off when doing this?
> The key cylinder is (1) off, (2) position 1, (3) on and then (4)
> start. Do you go from 1-2-3 back to 1?

On my '05, I simply press the odometer reset button, then turn the key
on, then release the odometer reset button. The codes you get this way
will be limited, but it's better than nothing. That $90 you spent for a
dealership diagnostic would probably have been better spent on a good
code scanner for your toolchest. I think every vehicle owner should
have one, even if they never turn a wrench.

If the plugs have 2k on them and they're Champions, they're fine; so is
the fuel system. That fancy 'cleaning' consists of a $3.00 bottle of
injector cleaner poured into the fuel tank...that's it. Dealerships
should be ashamed of the way they treat customers.

My suggestion to you: were I standing in your shoes (and I have), I
would spend the $200 for a decent code scanner (not a code reader - big
difference), and stand ready to read what the computer has to say.
After you have that information, you can proceed to repair the problem.
Yes, another $200 for tools seems excessive, but you will use it many,
many times, and it's good for all OBD-II vehicles, not just your Jeep.

Something tells me that your dealership HAD the codes, but chose not to
diagnose properly to add profits. I have seen this before. They'll
offer you a 'discount' if it happens again for another diagnostic
($10-off or some other nonsense), and only after they've taken hundreds
in profits, will they magically FIND the problem; then it's another $xxx
dollars to begin repairs, which will be equally inflated.