car starts - runs, but no idle

Drove into work this morning just fine.  Got into the car for lunch and it starts up fine, but won't idle - rpm just drops down then it's off.  I was able with some tricky foot work to get it over to the repair shop, but that's not a good way to drive!  I'm hoping this is going to be an easy fix - just need a new idle air valve? - thoughts?

This could be several different issues....you would need to start by checking for any codes in the system, to see if that leads to the culprit. Could be the IAC(idle air control) as you mention, but could also be a TPS(throttle position sensor), or something as simple as a vacuum leak. Lots of variables here, but I would see if it has any codes stored, and proceed from there.

as joel said, there are too many variables in todays car to be able to pinpoint. good luck.

When my 85 did this, it was the fuel pump. I forget exactly how I determined it was the 21 year old original pump causing the no-idle, but it was. I distinctly remember driving it from where it first died (it was in the smog inspection bay getting its first "smog" in 12 years when I put it back on the road 12 years of storage) to the store to buy the replacement pump, and then home to install it. I'd push in the clutch to shift, and it would die. I'd shift, let the clutch out and it would fire right back up.

I know it doesn't make sense that it could be the pump, but it was for me. I had the problem fixed less than an hour after it first occured. That was 7 years ago, and has never died at idle since. Runs like an L98 should.

So the car is back from the shop and it was the idle air control.  Guess the pintle got stuck or something.  Dealership had to get the part from Michigan so it was in the shop until Saturday.  But it snowed a bit during the week so it wouldn’t have been driven anyway.  Snows all gone so it’s with me again today!

Glad to hear you got it back, nothing worse than owning a vette thats "in the shop" ... trust me I know!

Ya...the pintles will get carboned up, and not move in/out properly. You can usually clean them, but it's better in the long run to replace.
Glad they were able to get it taken care of!

So I know the idle is controlled by the ECM, but why is there an adjustment screw at the throttle plates?  After the IAC repair it seems the car is running a little higher idle then before.  I would assume because it's not having to fight getting fuel in like before.  Right after I originally purchased the car I cleaned the throttle plates as they were wicked dirty and it ran a much higher idle then before so before I knew any better about ECM control I adjusted the screw out so to close the plates a bit, and that worked great.  Is there adjustment that works with the ECM?

to adjust the screw, back it out and then turn it in untils it just touches the arm and then 1/4 turn is where it should be set to. if i remember correctly when i replaced my IAC, it said to drive the car at approx 38-39 mph for a couple of miles so it can adjust itself. the idea is not to let the car go into overdrive.

The screw keeps the throttle plates from jamming / sticking closed. The adjustment also affects the TPS closed-throttle voltage, and the IAC counts. TPS at closed throttle should be .5 Volt, and IAC counts should be 20-40. The screw affects more than just throttle plate position.