I have a 95 Dakota with a 5.2. I have recently changed the PCM and also did a TB cleaning. I also have replaced the IAC. Now I have a high idle issue. The engine will start, rev to 2000 and then drop to around 1000 RPM. After it warms up it slowly climbs to 1400 to 1500. So far I checked everything I can think, Did the propane test for a vac leak. The TPS is at 800 ma and will slowly climb to 3.8 vdc when you turn the throttle. I just got a scanner tool from friend and the result are as follows. TPS is at 0%, IAC is at 0% and I verified that by checking the plunger. Colant temp showed 208. Vacuum shows 18 hg. Is this a result of the computer being new? What else to check?

 

The idle speed is solely controlled by the IAC, so give it a week and if it doesn't fix itself, you may have gotten a bad IAC. When I replaced my IAC and reset the computer, it idled high for about a week.

Also, I have never used a scan tool... what the heck does it mean for those sensors to be a 0%?

 

I'm still learning the scan tool myself. From what I can figure the PCM figures out how far to open the IAC by the %. If it's closed it's 0% if it's all the way open it's 100%. Same with throttle at 0% it should be at idle. I'm hoping that this resolves itself. All the sensors seem to check out. I used a mopar IAC. Just because everyone complains about the aftermarket ones. I had a newer Jeep with similar issues once. I put in a new battery and it took a few trips to reset everything. Weird part is in drive it idles at 600 rpm. Only in park or neutral it will hang at 1500.

 

Oh, ok. That makes sense. If you want a better understanding of what those sensors should be reading, you can download the 1995 Dakota Factory Service Manual located in FAQs or FAQ2 if you haven't already.

Yeah, that sounds exactly like what mine did. It should resolve itself. I wouldn't worry about right now. Like I said, give it another week or so.