saturn high idle and vibration

i have a 1999 saturn sl1. when i start the car the rpm shoots up to 2500 then returns to 1000. when i put the car in park after driving, the rpm shoots up to 2000 and stays there. there is also a loud vibration at all times. i'll be sitting at a stoplight and the steering wheel vibrates, the whole car vibrates. also, when i turn the a/c on, i lose acceleration, like the car is not getting enough gas. the car only has 56,000 miles on it. any suggestions on where to start looking for the problem?

Could be a throttle positioning sensor. You will always lose a decent amount of power running the A/C. Takes a whole lot to cool down the cab!

First, replace your Engine Coolant Temperature Sensor. Then clean your throttle body including your Idle Air Control valve. SHould be good to go.

Vibration: bad top motor mount. Replace and you wont even know the car is on.

A/C: As stated you will always feel a big difference in power with it on especially in a SOHC car.

First, replace your Engine Coolant Temperature Sensor. Then clean your throttle body including your Idle Air Control valve. SHould be good to go.

Vibration: bad top motor mount. Replace and you wont even know the car is on.

A/C: As stated you will always feel a big difference in power with it on especially in a SOHC car.


Quoted for truth.

I had the same problem with my 98 Saturn SL. It started to idle around 2000 rpm when warm. I replaced both the engine coolant temp sensor (ECTS) and the throttle position sensor (TPS) with new ones from AutoZone. Took care of the 2000 rpm idle problem and it runs fine now.

Rob