Just bought a 01 GCL. It's a 4.0L with 67K miles. With the engine warm the idle fluctuates from ~700 down to about 500. It intermittently stalls. It does this if it's in gear or not. It has a code of P1294. Runs great on the highway.

I was told it sat all winter (Michigan) so the battery was dead. He jumped it, then this problem started. I went ahead and put a bottle of Heet in the gas tank and filled it up with premium just in case it might have some moisture in the tank.

Found a couple of posts about the IAC. Any suggestions on how to check if that's operating correctly? Or just pull it and clean it?

Thanks

 

sounds like the Throttle pos sensor problem that 4.7l have. I have not had anything to do with a 4.0. try doing a search on the topic, you will find lots.

 

Did a little more testing. It idles fine when cold. The problem starts after it gets up to temp. If I turn the AC on it will idle ok, but seems a little low around 500.

Thanks

 

could be tps but typically a bad tps will cause idle surge,bucking and poor drivability...a bad iac can cause low idle and stalling,i don't understand the a/c thing tho...did you try the key on/off to see if you get a code?

 

Got a P1294 code "Target idle not reached". Will have to look at my notes again to see what the text readout was.
I read somewhere to turn on the AC which puts a load on the engine and the IAC should respond by bumping the idle up a little, same with putting it in gear.
So it looks like the IAC is a good place to start. Is is better to just replace or has anyone had luck just cleaning and reinstalling?

 

Got it fix. Found a post on another forum with the exact same symptoms, had dead battery then car wouldn't idle. The fix was to warm up the engine, shut it off and disconnect the negative battery cable for 30 minutes. Then start the car and let it idle for a few minutes. It's been fine ever since. Easiest fix ever! Thanks for the replies.

 

unhooking the battery for 30 minutes just resets/clears the computer and if there is an issue it will come back,the code you got indicates the IAC (as discussed earlier) or a vaccum leak so if/when it comes back start there