Jeep Wrangler High Idle Problem
 

Hello Everyone:

I have a 97 TJ and 95% of the time it idles perfectly. However, about
5% of the time, usually when the vehicle has been run for more than 20
minutes or so, the idle in neutral or park will shoot up to between
1200 and 1500 RPM. The only way to get it to stop is to put the
vehicle into gear or to restart the car. If I restart it, it will not
happen for a while, but it eventually comes back. The TPS was recently
replaced, and I just replaced the idle air control valve, thinking
this may have been the problem, but it still has the same effect. I'm
thinking now that it may be the coolant temperature sensor (something
wacky when the engine is hotter making the vehicle run at higher
speeds??). Any suggestions? I'm hoping its not my computer...

Re: Jeep Wrangler High Idle Problem
 

97tjMike wrote:
> Hello Everyone:
>
> I have a 97 TJ and 95% of the time it idles perfectly. However, about
> 5% of the time, usually when the vehicle has been run for more than 20
> minutes or so, the idle in neutral or park will shoot up to between
> 1200 and 1500 RPM. The only way to get it to stop is to put the
> vehicle into gear or to restart the car. If I restart it, it will not
> happen for a while, but it eventually comes back. The TPS was recently
> replaced, and I just replaced the idle air control valve, thinking
> this may have been the problem, but it still has the same effect. I'm
> thinking now that it may be the coolant temperature sensor (something
> wacky when the engine is hotter making the vehicle run at higher
> speeds??). Any suggestions? I'm hoping its not my computer...
>

Does the check engine light come on? Have you checked to see if there
are any trouble codes?

Jeff DeWitt

Re: Jeep Wrangler High Idle Problem
 

97tjMike wrote:
> Hello Everyone:
>
> I have a 97 TJ and 95% of the time it idles perfectly. However, about
> 5% of the time, usually when the vehicle has been run for more than 20
> minutes or so, the idle in neutral or park will shoot up to between
> 1200 and 1500 RPM. The only way to get it to stop is to put the
> vehicle into gear or to restart the car. If I restart it, it will not
> happen for a while, but it eventually comes back. The TPS was recently
> replaced, and I just replaced the idle air control valve, thinking
> this may have been the problem, but it still has the same effect. I'm
> thinking now that it may be the coolant temperature sensor (something
> wacky when the engine is hotter making the vehicle run at higher
> speeds??). Any suggestions? I'm hoping its not my computer...
>

Does the check engine light come on? Have you checked to see if there
are any trouble codes?

Jeff DeWitt

Re: Jeep Wrangler High Idle Problem
 

97tjMike wrote:
> Hello Everyone:
>
> I have a 97 TJ and 95% of the time it idles perfectly. However, about
> 5% of the time, usually when the vehicle has been run for more than 20
> minutes or so, the idle in neutral or park will shoot up to between
> 1200 and 1500 RPM. The only way to get it to stop is to put the
> vehicle into gear or to restart the car. If I restart it, it will not
> happen for a while, but it eventually comes back. The TPS was recently
> replaced, and I just replaced the idle air control valve, thinking
> this may have been the problem, but it still has the same effect. I'm
> thinking now that it may be the coolant temperature sensor (something
> wacky when the engine is hotter making the vehicle run at higher
> speeds??). Any suggestions? I'm hoping its not my computer...
>

Does the check engine light come on? Have you checked to see if there
are any trouble codes?

Jeff DeWitt

Re: Jeep Wrangler High Idle Problem
 

97tjMike wrote:
> Hello Everyone:
>
> I have a 97 TJ and 95% of the time it idles perfectly. However, about
> 5% of the time, usually when the vehicle has been run for more than 20
> minutes or so, the idle in neutral or park will shoot up to between
> 1200 and 1500 RPM. The only way to get it to stop is to put the
> vehicle into gear or to restart the car. If I restart it, it will not
> happen for a while, but it eventually comes back. The TPS was recently
> replaced, and I just replaced the idle air control valve, thinking
> this may have been the problem, but it still has the same effect. I'm
> thinking now that it may be the coolant temperature sensor (something
> wacky when the engine is hotter making the vehicle run at higher
> speeds??). Any suggestions? I'm hoping its not my computer...
>

Does the check engine light come on? Have you checked to see if there
are any trouble codes?

Jeff DeWitt

Re: Jeep Wrangler High Idle Problem
 

On Aug 12, 9:42 pm, Jeff DeWitt <JeffDeW...@nc.rr.com> wrote:
> 97tjMike wrote:
> > Hello Everyone:
>
> > I have a 97 TJ and 95% of the time it idles perfectly. However, about
> > 5% of the time, usually when the vehicle has been run for more than 20
> > minutes or so, the idle in neutral or park will shoot up to between
> > 1200 and 1500 RPM. The only way to get it to stop is to put the
> > vehicle into gear or to restart the car. If I restart it, it will not
> > happen for a while, but it eventually comes back. The TPS was recently
> > replaced, and I just replaced the idle air control valve, thinking
> > this may have been the problem, but it still has the same effect. I'm
> > thinking now that it may be the coolant temperature sensor (something
> > wacky when the engine is hotter making the vehicle run at higher
> > speeds??). Any suggestions? I'm hoping its not my computer...
>
> Does the check engine light come on? Have you checked to see if there
> are any trouble codes?
>
> Jeff DeWitt

Engine light never came on, however I did check codes and this came up
when I checked a few weeks ago:

42 An open or shorted condition detected in the auto shutdown relay
circuit. An open condition detected in the ASD relay output circuit.
An open or shorted condition detected in the fuel pump relay control
circuit. An open circuit between PCM and fuel gauge sending unit.
Circuit shorted to voltage between PCM and fuel gauge sending unit. No
movement of fuel level sender detected.


However, I remember seeing that code a few months before this problem
came up. I reset the codes a few weeks ago, and the other day I
checked and that code hasn't come back.

Re: Jeep Wrangler High Idle Problem
 

On Aug 12, 9:42 pm, Jeff DeWitt <JeffDeW...@nc.rr.com> wrote:
> 97tjMike wrote:
> > Hello Everyone:
>
> > I have a 97 TJ and 95% of the time it idles perfectly. However, about
> > 5% of the time, usually when the vehicle has been run for more than 20
> > minutes or so, the idle in neutral or park will shoot up to between
> > 1200 and 1500 RPM. The only way to get it to stop is to put the
> > vehicle into gear or to restart the car. If I restart it, it will not
> > happen for a while, but it eventually comes back. The TPS was recently
> > replaced, and I just replaced the idle air control valve, thinking
> > this may have been the problem, but it still has the same effect. I'm
> > thinking now that it may be the coolant temperature sensor (something
> > wacky when the engine is hotter making the vehicle run at higher
> > speeds??). Any suggestions? I'm hoping its not my computer...
>
> Does the check engine light come on? Have you checked to see if there
> are any trouble codes?
>
> Jeff DeWitt

Engine light never came on, however I did check codes and this came up
when I checked a few weeks ago:

42 An open or shorted condition detected in the auto shutdown relay
circuit. An open condition detected in the ASD relay output circuit.
An open or shorted condition detected in the fuel pump relay control
circuit. An open circuit between PCM and fuel gauge sending unit.
Circuit shorted to voltage between PCM and fuel gauge sending unit. No
movement of fuel level sender detected.


However, I remember seeing that code a few months before this problem
came up. I reset the codes a few weeks ago, and the other day I
checked and that code hasn't come back.

Re: Jeep Wrangler High Idle Problem
 

On Aug 12, 9:42 pm, Jeff DeWitt <JeffDeW...@nc.rr.com> wrote:
> 97tjMike wrote:
> > Hello Everyone:
>
> > I have a 97 TJ and 95% of the time it idles perfectly. However, about
> > 5% of the time, usually when the vehicle has been run for more than 20
> > minutes or so, the idle in neutral or park will shoot up to between
> > 1200 and 1500 RPM. The only way to get it to stop is to put the
> > vehicle into gear or to restart the car. If I restart it, it will not
> > happen for a while, but it eventually comes back. The TPS was recently
> > replaced, and I just replaced the idle air control valve, thinking
> > this may have been the problem, but it still has the same effect. I'm
> > thinking now that it may be the coolant temperature sensor (something
> > wacky when the engine is hotter making the vehicle run at higher
> > speeds??). Any suggestions? I'm hoping its not my computer...
>
> Does the check engine light come on? Have you checked to see if there
> are any trouble codes?
>
> Jeff DeWitt

Engine light never came on, however I did check codes and this came up
when I checked a few weeks ago:

42 An open or shorted condition detected in the auto shutdown relay
circuit. An open condition detected in the ASD relay output circuit.
An open or shorted condition detected in the fuel pump relay control
circuit. An open circuit between PCM and fuel gauge sending unit.
Circuit shorted to voltage between PCM and fuel gauge sending unit. No
movement of fuel level sender detected.


However, I remember seeing that code a few months before this problem
came up. I reset the codes a few weeks ago, and the other day I
checked and that code hasn't come back.

Re: Jeep Wrangler High Idle Problem
 

On Aug 12, 9:42 pm, Jeff DeWitt <JeffDeW...@nc.rr.com> wrote:
> 97tjMike wrote:
> > Hello Everyone:
>
> > I have a 97 TJ and 95% of the time it idles perfectly. However, about
> > 5% of the time, usually when the vehicle has been run for more than 20
> > minutes or so, the idle in neutral or park will shoot up to between
> > 1200 and 1500 RPM. The only way to get it to stop is to put the
> > vehicle into gear or to restart the car. If I restart it, it will not
> > happen for a while, but it eventually comes back. The TPS was recently
> > replaced, and I just replaced the idle air control valve, thinking
> > this may have been the problem, but it still has the same effect. I'm
> > thinking now that it may be the coolant temperature sensor (something
> > wacky when the engine is hotter making the vehicle run at higher
> > speeds??). Any suggestions? I'm hoping its not my computer...
>
> Does the check engine light come on? Have you checked to see if there
> are any trouble codes?
>
> Jeff DeWitt

Engine light never came on, however I did check codes and this came up
when I checked a few weeks ago:

42 An open or shorted condition detected in the auto shutdown relay
circuit. An open condition detected in the ASD relay output circuit.
An open or shorted condition detected in the fuel pump relay control
circuit. An open circuit between PCM and fuel gauge sending unit.
Circuit shorted to voltage between PCM and fuel gauge sending unit. No
movement of fuel level sender detected.


However, I remember seeing that code a few months before this problem
came up. I reset the codes a few weeks ago, and the other day I
checked and that code hasn't come back.

Re: Jeep Wrangler High Idle Problem
 

97tjMike wrote:

> Hello Everyone:
>
> I have a 97 TJ and 95% of the time it idles perfectly. However, about
> 5% of the time, usually when the vehicle has been run for more than 20
> minutes or so, the idle in neutral or park will shoot up to between
> 1200 and 1500 RPM. The only way to get it to stop is to put the
> vehicle into gear or to restart the car. If I restart it, it will not
> happen for a while, but it eventually comes back. The TPS was recently
> replaced, and I just replaced the idle air control valve, thinking
> this may have been the problem, but it still has the same effect. I'm
> thinking now that it may be the coolant temperature sensor (something
> wacky when the engine is hotter making the vehicle run at higher
> speeds??). Any suggestions? I'm hoping its not my computer...

Clean the TPS connector. Go to an electronics parts store and buy some
contact cleaner or WD40 works. Disconnect the TPS, clean, connect and
disconnect several times, blow dry, then use some dielectric grease on the
the connector seal ring to keep moisture out.

--
Will Honea