What's wrong if I have an erratic idle only when in park or neutral?

Answer by  mdjames26 (533)

Check the linkage under the hood. There is a cable that connects the accelerator inside the car to the engine and it pulls back when you press the gas. The cable will run to the engine and attach to a small hook with a spring. It could be spaced incorrectly.

Answer by  Brandon55 (1719)

A vacuum leak or a computer issue can cause what you are describing. In park there is no load on the engine and the computer is trying to constantly adjust.

Answer by  Amber40 (24961)

IT sounds like you have a failing idle air control valve. When these go bad they can cause the cars idle to fluctuate. Have a mechanic look at it or test it yourself and see if it needs cleaned.