Dunno if it could be related or not but, while you have the throttle body off look down inside and see if you have any signs of oil leakage... i reason i mention it is i had an issue with a rough idle with some bucking once in awhile when iwould hit the throttle. Replaced all the common things and i turned out that it because the plenum gasket has a small leak. just a thought.

 

Finally got around to cleaning the throttle body and iac today. The under side of the TB and the IAC were really black. I took it for a drive and within a few blocks still felt the bad idle. Not sure if it might take a few miles for the computer to re-tune but it felt exactly the same.

While I was in there I checked the plenum plate and it did have oil on it. Now the question is if I should change the plenum gasket, change the tps or get a new IAC. I'm assuming that I don't want to do the plenum plate unless I have to.

 

if you did not reset the PCM it can take up to 500 miles to relearn any changes.

 

I reset the PCM so I'm guessing 40 - 50 miles before I make any other decisions. I just expected some change after my work

 

I hope you installed regular Champion Copper plugs when you did the plug change?

Also could be a coil or a plugged injector. Have you ran some fuel injector cleaner like Seafoam in it yet?

 

I always use champion plugs in my vehicles. The only one that doesent get champion is my srt-4 which gets NGK.
I did put Some injector cleaner in a few tanks ago but it was just STP. I've never really heard of seafoam outside of what people seem to say here on the forum. Guess I'll give the stuff a try.

 

I don't personally like any additives, but if I have an issue like this Seafoam is the only one I will use.

 

I picked up a can of seafoam earlier this week and added it to a tank of gas. I've ran through 2/3 of the tank and im not seeing any difference in the idol. It seem especially bad now when I have the heater blowing on defrost.

Decided to go ahead and change the IAC today. I reset the pcm and then went for a drive and still didn't see any difference with the idle. I'll see how it goes in the next few days of driving but after seeing some oil on the plenum plate I'm thinking I may need to change that gasket next.

 

If it is leaking that could be where the problem lies. As long as you reset the pcm the changes should be felt right away.