Idle surging both in and out of gear.

[fredjacksonsan]

Here we go again......86 MGM, 5.0 liter, 140K miles. New idle air valve. In good state of tune. Clean air filter. Fuel pump/filter ok. No vacuum leaks that I've found.

On the gas, smooth as always. At idle however, in or out of gear, the idle surges, first dropping low and running rough enough to sometimes shake the engine, then coming back up to normal, then repeating. Cycle takes about 3-4 secs each time. Other than that no problems.

Any ideas about THIS idle problem?

Thanks in advance......

[auto trainy]

Try cleaning the egr valve and then check for carbon build up.

[fredjacksonsan]

Thanks, will do. Hope that'll cure it.

[88Marquis]

One of the problems i'm having as well and hopefully we'll find the solution quickly..does your car stall when cold? and shutt off after a stop if you dont wait to warm up for a while?

[fredjacksonsan]

Nossir, mine never had a cold problem, all the problems were across the board, hot or cold.