I've had odd idle issues ever since I bought this car. It will idle extremely high (3000rpm) while in park and the car is warm and idle around 1200rpm in gear. I can restart the car and it will run fine for a while, but the high idle will return. Part of the issue I'd had was bad fuel injector o-rings. After those were replaced, the problem got better and the car is drivable, but the problem still persists. I've also had this mystery vacuum line that I have no idea what it's connected to. The origin of the line traces somewhere beneath the battery and appears to go back up under the firewall. Does anyone have any ideas? I'm tired of this high idle issue

 

What year Monte? Which engine? Any pics of the mysterious vac line you mentioned?

 

01 3.4 V6. And the pic in the thread is the line.

 

You sure thats a vac line and not the washer fluid line?

 

Any idea where the other end goes to?

Running away from the engine like that, my thoughts are something like the evap canister, a vacuum ball, or HVAC.

Is the EVAP solenoid in that general area on the 3400?

 

I double checked. It is not. That was one of my first thoughts

 

If it's none of those 3, I can't think of anything else besides windshield washer line. Not a whole lot of hard plastic lines that it can be. What is on the other end when you trace it?

Even if it is WW, something is still jacked with the engine if it idles at 3k.

 

Check the IAC, idle air control, take it out, clean it, clean inside also with rag, q tips etc might fix this ?