Engine Performance problem
2002 Saturn SL2 4 cyl Two Wheel Drive Automatic 120000 miles
My Saturn SL2 has an intermittent fast idle. In park it idles at 2000 rpm and in drive it is about 1200 rpm. If you stop and start the engine the problem may or may not reoccur. No recent engine lights. Recently put plugs and wires. I have read that this could be the fault of the throttle position sensor or idle air control. If so, can I easily replace those myself (I am fairly capable, but do not want to throw parts at this.)
The symptoms of a faulty or failing IAC valve (Idle Air Control Valve) are not present in your issue. With a faulty IAC valve, the engine will rev up and down constantly, usually ending in a stalling engine.
I believe your problem lies with the throttle position sensor. Symptoms of faulty TPS are transmission shift issues, bucking and jerking, idle surging, engine cutting off, hesitation when taking off, surge while cruising down the highway.
Usually a check engine light will illuminate due to a faulty component. If your engine light is on, you can get the codes scanned with a diagnostic scanner for free at most local part stores such as AutoZone, or buy a scanner to keep and use it. This will help pinpoint the culprit out much quicker.
Below are removal/installation instructions for the TP sensor (Throttle Position).
Turn ignition off. Remove air induction hose between throttle body and air cleaner. Disconnect Throttle Position (TP) sensor harness connector. TP sensor is mounted on throttle body. See FIG. 3. Remove the 2 TP sensor screws. Remove TP sensor.