Engine/Transmission (1998.5 - 2002) Idle changes

[DMather]

I've been noticing that sometimes when I come to a stop the idle will sit at 900 or 1000 rpm instead of the normal 800. The TPS (I think it's referred to as POTS here?) seems to be clean and normal and only has about 12K on it.



I have not been able to see any correlation with anything else. . (. ambient temp, engine temp, etc. ) I've "popped" the throttle a couple of time but very seldom does it make a difference. If I shut down and restart it will idle at 800.



So, my question is: is there a sensor that is know for causing this kind of probem. It isn't interfering with anything... it's just annoying. (and noisy at drive throughs)

 

[JLandry]

Doug,



It could be a number of things, but without a Chrysler DRBIII scan tool to actually read the sensor outputs live, you're sort of stuck replacing things one-by-one until you stumble across the right item.



Did this start all of a sudden or was anything else done to the truck beforehand?



You say the APPS (Accelerator Pedal Position Sensor) has only 12K miles on it? It's still possible this new APPS is already having problems (it's happened to others), but I would think that would low on the list of possibilities. Don't rule it out though. You can buy a new TPS (just the reostat part of the APPS) from TDR member Timbo for about $145.



Have you checked to make sure nothing is restricting the throttle cable or could something be preventing the APPS from returning fully to the idle position? You can take the black plastic cover off the APPS and examine the bell crank to make sure it's fully against the idle stop next time this happens.



I could also conceive of such a problem being caused by the CPS (Crankshaft Position Sensor) sending faulty engine speed signals to the ECM.



Good luck,



John L.