Rough idle at stops?? RPM bouncing like crazy.

[Mr240dude]

Hey everyone, for the past month my car has been idling heavily and shaking at stops, it seems to happen frequently. Holding on to the brake seems to be worse as oppose to keeping it in park. The RPMS will bounce from 500 all the down to around 200 or less. Yesterday the car actually shut off and I turned it back on while I was at a stop. Does anyone have a clue what this may be? I am hoping it's something simple like a vacuum leak. Any help would be appreciated, thanks!

[PapaSmurf2k3]

I was going to say, look for vacuum leaks first. Idle air control valve second.

Is the car an automatic? Hopefully your torque converter isn't partially locked up or something.

[Mr240dude]

The car is an automatic, is vacuum leaks the most probable reasons for this?

[PapaSmurf2k3]

Usually yeah, followed by dirty/faulty idle air control valve, and bad MAF/MAF wiring.

[Mr240dude]

Usually yeah, followed by dirty/faulty idle air control valve, and bad MAF/MAF wiring.

I took the car to the shop and they claim they read codes on the car involving the fuel running rich, they pretty much shrugged their shoulders and gave me no solution. They mentioned it may be injectors or something else, should I assume they are playing the guessing game? I really hope this is is something simple, I will need a second opinion from another shop.

Today the car shut off when i was turning down my block, I had my foot off the gas and it shut off....any ideas?

[asoomal]

Yeah...avoid that shop from now on...

+1 on checking vacuum leaks.

Also check the TPS as per the FSM.

[The Inflicted]

Does the car do this when you first start it, or only after it warms up?
If it doesn't idle properly for a few minutes before warming to temperature you can probably rule out the idle air control valve.

[PapaSmurf2k3]

If its running rich through the entire RPM band, its more than just the idle air control valve.
Check MAF, O2, and coolant temp sensor.