High Idle - After Driving; Weird TPS...

I'm hoping someone might be able to explain my TPS readings ...and also suggest some other things which may be causing my current high idle.


I came across the following TPS readings:

At the 3-pin connector: A reads 6.5v; B reads 4.80 closed / 0.02 WOT; D reads 0.02 (before I added a ground it was 1.00+). These readings are as low as I can get by adjusting the rotation of the sensor. From searching I gather both A and B readings are way off. Does this mean the TPS is gone or could something else cause inaccurate readings?

Some background on my general idle problems...I was problem free untill about a month ago (when it started getting cold out). I had been experiencing, what I would call, a sticky throttle where the it would often not return to idle RPMs; if I revved up to 2500 RPMs, it wouldn't drop down at all (at stops/start up, etc this wasn't good). Popping the hood and pushing the throttle arm back would bring the idle back to normal (until the next time I brought the RPMs back up with the pedal). Cleaning out the TB, the return spring, cables etc did a bit but when I added a second throttle return spring it solved it. No problems until the current one.

DESCRIPTION of my curent high idle...
At start up I idle around 700RPM. After driving for a bit (usually a 10min freeway, 60mile/hr commute) it will drop in RPMs, when I release the pedal, but only come down to 12-1500 (usually 1200 in drive and 1500 in park). If I leave it in park idling for a while it will eventually come back down to 900-1000RPM after some time. Pushing in the throttle return has no effect. I've cleaned the IAC, TB (one year ago). I'm wondering what else to check once I get these TPS readings back to normal...vacuum leaks? How can I test the manifold gasket/TB seating?

I would be really suspicious of the TPS. You did a good thing to splice in a new ground, that cures most of the peripheral TPS problems, but if you are getting up in miles, it may be time for a new one. TPS problems can be intermittent, and really difficult to diagnose. I would bet that will cure your idle problems, and make it adjust properly.
I actually drilled a "tiny" hole in the TPS body, and about every 6 months I shoot in some contact cleaner. That seems to clear up any TPS-related issues, and keeps it working like new.

i have the same idle issue.. havent gotten into troubleshooting yet but i was going to start with a new TPS..... as far as checking the seal on the manifold and TB.... spray a little carb cleaner around the mating surfaces and if there is a vacuum leak it will bump the idle up when it sucks the cleaner into the system.. DO THIS ON A COLD ENGINE ONLY!!!! you have a few minutes before the exhaust manifold gets hot anyways.. let us know how you resolve this
mike

Some Developments...

So I went at it again yesterday...the TPS is still giving me rather odd readings. My ground is fine (less than 0.1v); A is at 6.5v (sometimes goes to 6.7v); and B can be set to 82% pf A (but shoots RPMS to 2K if I do) and at WOT is out of whack. Can ANYONE confirm what these readings mean??? Is this TPS definately shot or is it a problem with whatever is shooting input to it at 6.5v??? Help.

I also played around by closing off the IAC and main TB port with my hand while idling...closing off the IAC had a small difference but I was surprised to find the amount suction/air going through with the butterfly 'closed'. I think may try adjusting the 'stop/adjustment screw' and see if I can close it more; maybe the previous owner messed with it.

Since changing vacuum lines/cleaning valve cover in May I've had a surprising amount of blowby...the airbox, TB, and manifold is all quite bad.

On automatic Jeeps, you are supposed to use the four pin connector and not the three pin. Hope this helps.

I kind of explained it wrong in my post...I am talking about the 'four pin connector'. The four pin connector only has three pins when you look at it...why...I don't know.