Hey guys, Im having trouble with my truck and don't really know what is going on and Im looking for a bit of insight. First off, my truck is a '99 Dakota Sport 5.2L.
Just a couple weeks ago, I replaced the IAC and TPS because I was having a problem in which the rpms would stay up high when I pushed in the clutch. It turned out to be the TPS as far as I could tell. Regardless, after replacing those two things and resetting the PCM, the problem went away. For a day.
On cold starts, the it seems to struggle idling. When driving or giving it gas, it is perfectly fine, but as you let off the gas, it struggles to idle. But it will only do this for about 2 miles of driving. Which makes me think that it is only an issue while in Open Loop operation. But maybe that has nothing to do with that.. I don't know. Anyways, after about 2 miles, all is well and there is no problems. However.... Once I am within a couple of miles of work/home (after about 15-20 mins of driving) I will go to shift and as I take my foot off the gas and push in the clutch, the rpm's jump up to 3000 like my foot is still on the gas for 2-3 seconds, then falls back down to normal. Since it seems to start to do this consistently near the same spot every day, I have kind of played with it to get a better idea of what is happening. Once it starts to do it, I will tap the gas while in gear and I can feel and hear the engine revving like my foot is holding the gas for 2-3 seconds. Similarly, while holding the clutch in, I will tap the gas and the rpm's jump up to 3000 for 2-3, again, like I'm stepping on the gas. I am quite sure the throttle is not sticking, because it snaps right back. And it only does this after 15-20 mins of driving.
I don't know if these issues are related, but they both started right after replacing the IAC and TPS and resetting the PCM. Any Ideas?? Any help is greatly appreciated. Thanks guys.

 

map sensor??

 

Maybe... I could I check that?
It just seems odd that the MAP sensor would go bad when it seemed like putting on a new TPS fixed the issue I had before all of this.

 

sorry, Meant to say "How could I check that?"

 

the fastman said to turn the key to on, do not start, then push gas pedal slowly to the floor then let it up. it sets up the tps to the computer.

 

Could be any of the 3 sensors. Whatever it is, it knows better and closes the IAC when i sees the fault.

 

Did you clean the Throttle Body where the IAC goes? I have had good luck with Seafoam for stuff like that.
Also, did you set the IAC before installing it?

 

I did not clean the TB. I was planning on doing it when the rain stopped and it gets a little dryer. How do you set the iac?

 

I will have to check the book for the Pintle length, but before installation the manual state to adjust the pintle length (the distance from the pintle(plunger on the end of the IAC)) to a preset distance from the plastic part. Usually you can just push it in or pull it out to the needed distance.

 

Ok, so i cleaned out the TB. Now ot seems to start up and idle just fine for a little bit, then it starts to idle really rough.. To the point that I can feel the whole truck shake. PLUS, now its back to the rpms staying up high until I come to a complete stop (the reason I replaced the iac and tps im the first place). So I will be driving down the road and when I push the cluch, the rpms fall to only about 1500 until I come to a COMPLETE stop, then they fall to 800ish (normal)..