2004 Saturn ION II - Car Idles High in Park & Neutral

I’m having headaches with my Saturn. For the past two and a half years I’ve taken the car to a dealer here in Atlanta and every time I take it in I pose this question to the dealer, “When I’m driving occasionally (very random) when the car is in driveit will start to idle high (about 2100 RPM) but every time I put the car Neutral or Park then it shoots up to 2100 RPM. Why is it doing this?”

The first time I asked them this they turned around and charged me $90 to clean a carb build up on the injector. They said it was a typical remedy but after I left it did it again on the drive home. They wouldn’t research it more without charging me $90/hr for a minimum of 2 hours for testing the system.

After reading the blogs on yahoo, google and other sites everything pointed to the “Throttle Body Position Sensor”. It looks easy to replace but I want a second opinion on this assessment (without a $180 fee)

You probably mean the throttle position sensor. See an independent mechanic and stay away from the dealer. There are several other reasons that can cause this so they need to be checked out. Dealerships have technicians that are parts-replacers. They hope to fix the problem by replacing parts and rarely troubleshoot anything. You need a second opinion before you go broke at the dealership.

The problem might be with a defective Idle Air Control valve.

The next time the idle is high, locate the IAC valve and tap on it with the handle of a screwdriver. If the idle speed changes when doing this replace the IAC valve.


Well my reason for saying the Throttle Position Sensor is that if I shut the car off and turn it back on then it works properly immediately and that’s without touching the gas pedal. I’m hooked to my Haynes manual lately. I guess I’ll tinker some this weekend and see what I can come up with.

But, we are saying: idle air control valve.

Yep! A faulty IAC valve will act that way.


did you ever find the remedy for your problem my 03 ion is doing the same exact thing please help if you can thanks

I have an ‘03 ion also that is reving high around 2.0 in neutral and during shifting from drive to reverses. Should I try replacing my IAC?

you should try tester’s advice up above first.