Very Fast Idle

ALAKSANSAS

MEMBER
SATURN

My son, s 1999 SL2 Saturn with a 1.9 dual overhead cam, 5 speed transmission suddenly began idling at 3,000 RPM. Runs and idles smooth, just very fast, hot or cold.

I have checked for vacuum leaks and found none. Changed the map sensor, did not make a difference.

I can manually control the ariflow with my hand and it idles down fine. I have checked the pcv valve, it works fine. The computer shows no codes.

Any suggestions? We rebuilt about 5,000 miles ago and runs great.

Saturday, February 17th, 2007 AT 4:53 PM

3 Replies

SERVICE WRITER

MECHANIC
9,123 POSTS

Still sounds like a vaucuum leak, but is there a heavy carbon build up in the throttle body causing in th stick open a little. Or anything keeping the throttle open a little?

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Saturday, February 17th, 2007 AT 4:57 PM

ALAKSANSAS

MEMBER
2 POSTS

Thanks for your response,
I removed the part of the mainfold that houses the butterfly trhottle valve and throttle position sensor. Cleaned everything, but still doing the same thing.

I also called a local gm service center. They had one doing the same thing, could not figure it out, sent it to Saturn. Saturn service won't give me any help. Just bring it in.

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Saturday, February 17th, 2007 AT 5:10 PM

SERVICE WRITER

MECHANIC
9,123 POSTS

Just for the heck of it.
I have seen a lot of problems with the coolant temp sensor on these and with different symptoms. Cheap to replace, but at least pull it out and look for any cracks on it. It's on the driver's side on that one I believe.

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Saturday, February 17th, 2007 AT 5:31 PM