Idle/Throttle Issues

[chadstoks]

Hey everybody!

I have a 2003 Sport, 3.7 155,000 miles.

For the last few weeks she's been idling much higher than it should be, especially when I first start it. I did a little reading on here and based off some suggestions I removed the IAC and cleaned it and the throttle body. It seemed to make a little difference but it didn't completely fix the issue.

It seems to act up more when it is cooler outside but it has its moments at full operating temperature as well. I've also noticed that it seems to be affecting dropping into 'passing gear' while doing 45-50 going down the road. I can give full throttle and it will remain in the current gear, but not all the time, as in the same 10 minute window it will act up and act normal.

I feel like I need to replace the TPS or IAC but would prefer to not just throw parts at her and see if they stick.

Any advice??

Thanks in advance!

 

[Conundrum2006]

If there is a problem then TPS is more likely because it feeds information into the PCM. Which should affect how it shifts.
There should be a procedure for testing it.
I also may be wrong on how the TPS affects shifting in the newer libertys on the old Cherokee it would cause a lot of problems.


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[LibertyTC]

After cleaning IAC, how high is the rpm when you start it cold? What is outside air temp?
When cold mine idles at around 1200rpm until it warms up to above 1/4 on temp gauge.
I can then kick it down a bit, but still wont idle at 600 rpm /normal until it is driven/ fully warmed up.
The IAC controls the idle, so if it is still acting up, replace the IAC with a Mopar one and then see how it performs/drives.
Is the throttle plate opening and closing smoothly, without sticking at all?

 

[jeepinwyoming]

I had the same issue. I cleaned the IAC and throttle body. I also ended up replacing the TPS. And changed the plugs. All of that seemed to cure the problem for me.

 

[MTKross]

So strange! I'm experiencing that EXACT same issue now. Have been chasing it for awhile. Have all new plugs, IAC, crankshaft sensor as well as cleaned the throttle body. Still does it? Only thing I haven't swapped is the TPS


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[chadstoks]

Hey guys, sorry for the delayed response, life is busy! I put in a new TPS and knock on wood the issue has been gone since.

Thanks for the great info!