1994 surging idle
 

Hi folks. I've got a 1994 coupe automatic, it has about 85000 miles on it. Runs well and all that, but it has an idle problem. It surges up and down, with a frequency of about 3-4 seconds, occurs in both neutral and in drive, and does this this with the foot OFF the gas pedal. Only in idle. goes from about 600 rpm to about 1200 rpm. When you accelerate, it drives normal.

The car is at the mechanics right now, but I have little faith in him right now. He changed a couple spark plugs and some wires, but it's still doing it.

Any ideas what to look for?

Check engine light does function, but it's NOT on, so no codes in the computer.

RE: 1994 surging idle
 

1st thing to do on idle hunting like your car is to clean the throttle plates and throttle bore. Carbon build up on throttle plates can cause idle problems. All port fuel injected engines have this problem. Drive your car in off the road and shut the engine off and engine vapors inside the intake have no where to go so they just cook and coat the throttle plates. Clean with a small wire brush and carb spray. Then after cleaning, disconnect your battery for a couple of minutes, then reconnect and go drive around to let it relearn idle. See if that helps you. [8D]

RE: 1994 surging idle
 

What is your gas milage like??

check the PCV valve ($2). Does the car run better when cold? when hot?