When I start my 2000 1500 5.2L after leaving it over night or for a few hours it's idles at like 950ish then like just under a minute later it starts shaking like it'll stall for about 30 seconds thenjumps to about 1050for a second then right back down toaround 950. I drove it for a few miles and I notice a few minutes later that it's dropped down to 600ish. If I park and start a few minutes later it starts normally at 600ish with no shaking or erratic idling. I just replaced the IAC and this problem seems to of started after that. could this be aTPS or MAP sensor issue? The problem seems to be engine temperature related. Also last week I was on the highway and I felt a jerk like it had just dropped greatly in rpms by the time I looked at the rpm gage it was back to the proper rpm speed so I'm not sure exactly what happened. I just checked the tranny fluid and changed the oil so I don't think it's a fluid problem.

 

cold idle is about 1000rpm's give or take.

reset the idle air counts:
http://www.bionicdodge.com/Download/...a%20Magnum.pdf

The best way to do this is with a scan tool at the dealer, butthe manual way works ok as well.

If the problem is happening once the engine warms up, it might be a bad pre-CAT O2 sensor.

 

if the problem started only with the install of a new IAC, i'm going to disagree with squirrels on the need to reset the idle air counts and say that you've probably got a bad IAC. i had to replace mine recently and went through 4 bad ones before i got a good one. two bad ones from Autozone (one surged but didn't throw a code, the other couldn't even keep the truck running and threw a code). two bad ones from Advance/GP brand (cold idle at 2000 rpm). get either a SMP brand or Mopar (dealer).

 

I'm on my 4th one as well, 2 from Federated, 2 from Mopar. It's been a week on my 4th one and so far it's still running. BTW, no codes on any of them.

My mechanic replaced the battery this last time because it had a dead cell. He said he thought it was causing the motor on the IAC to go bad because of voltage problems, we'll see.

 

Mine would shake when idling after I started driving it; Pre-cat o2 Sensor fixed it easy.

 

I'm not sure thatIAC is defective everything seems fine other then at cold start. That's odd that IACs would be so defective. Doesn't really shock me though considering how cheap and universal the part is.Still considering how important this part is in starting and keeping your truck running you wouldn't think companies would make these so half assed.

 

It's all about that Dollar Sign lol.