So I recently just replaced my throttle body and cleaned it up. The problem I am having is as this...

NEW** Plugs, Wires, "Ignition System", Fuel Pump, Fuel Filter, Cold Air, MAF, Clean Throttle Body and Plenum. All Grounds are Good. NEW**

My car when warm idles around 550-600. I noticed that some times when I go for a short drive sometimes or longdrive doesn't matter... My car stalls out sometimes...

When its warm it has a rough idle... Gets as low as around 200rpm and then goes back up to 550-600rpm. That only happens sometimes though. Not all the time.

But I noticed a lot when I'm coming back from a drive when I'm going to park or put it in reverse and park "right" after or as I'm parking it just shuts off... But it starts right back up and runs perfectly fine after that... But if I let it sit the rough idle comes back?

Anyone have any suggestions?

 

**UPDATE**

So I am in my Automotive class right now and I was showing my instructors what happens to my car ^Described Above^

They were like... "hmm"

Pull the Mass Air Flow Sensor Connector off... After that happened it idle perfectly fine... I rev'd it up and everything... Didn't seem like it wanted to die...

They said next "Plug it back it" and when it did. The car stalled... I started it back up... It stalled... I started it back up and gave it some gas and left off of it and it idled fine for about 15 seconds and then it went back to the rough idle and then sounded like it wanted it die... (got done to like 100-200rpms) (sometimes it did just die)

So I pulled the MAF connector off and started it and it ran fine...

What could this indicate?

 

Well that indicates your maf sensor is bad. When its unplugged the computer no longer recieves the signal from the maf sensor telling it how much air is passing through it. The ecm just goes off of a default number that in your case was pretty accurate which made it idle and run fine. Replace the maf and you should be golden.

 

 

Maybe check the MAF burnoff relay and power relay first. they are the 3 relays sitting in the upper drivers side on the firewall. 15 bucks is better than 3 hundo

 

Also, try cleaning the MAF sensor with MAF cleaner before replacing it. Since you just had the throttle body off, be sure the TPS is set right and doesn't have a glitch in it. To verify no glitch, use a Snap On Vantage Lab Scope(I'm sure your school has one or something comparable) to sweep test the TPS. TPS being out of adjustment or clitchy can cause issues with the ECM's response to MAF data.

 

if its not the maf try the iac valve

 

I have a 350 out of an 89 IROC. Mine was doing exactly what yours was to the tee but not so much on the complete dying - maybe every two months it would completely die. But I have a 5 speed std so no load when stopped.

About two months ago I was not thinking and splashed water on the TPS. The TPS, of course, went out. Changed it and the idle was much improved. Still has a little rough idle but it also has an aftermarket cam. My problem was the TPS. And yes is was adjusted correctly at least a year before - can't say anymore than that.

I had suspected the MAF at one time and used the cleaner. It may be your MAF though. Never know.

IAC was changed also when checking the MAF back when. I just lived with it because I thought it was ALL cam problem.