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Discussion Starter #1
:) Hi there! I am new to this forum, I have been to 3 other forums and they are practically dead, so I guess i'll try here. =)

My engine originally had a blown head gasket. We hired a mechanic to fix it and now its back together and it runs great, my only concern is that the engine is idling between 2000 and 2500 rpms. I can't seem to get it to come down.

I have narrowed it down to these problems:

Vacuum leak.
Oxygen sensors. (they have never been changed, I bought the car from a previous owner, the car has 200k+ miles on it)
IAC (has also never been changed)

Oxygen sensors are 50 bucks a piece, and I need two of them. An IAC is 65 bucks. Before I spend 200 bucks, it would be nice to know exactly what my problem is. Any help or suggestions for narrowing this down would be greatly appreciated, thanks! =)
 

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I would chech the IAC valve. They go bad quite frequently. The diaphram will break over time.
 

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If the IAC was bad wouldn't the car stall rather than Idle too high?
I vote for the TPS.
 

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I guess you have never had one go bad on you. If the plastic diaphram breaks it will idle high. Been there done that. Mine broke because I cleaned it with a harsh solvent.
 

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No I have never had one go bad.
 

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I had a beater 3.1 chevy lumina long time ago and the idle air valve was messed up. going 65 down the freeway without the cruise control or my foot on the gas.
 

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Discussion Starter #8
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Thanks for the help guys! I ordered an IAC from kragen and I will be picking it up tomorrow. I will post back with my results!
 

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Discussion Starter #9
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Hi there! The IAC was indeed the problem and now car idles at around 800rpms, but the idling is rough. Any suggestions for that? =P
 

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I haven't done it yet but i am told that new oxygen sensors smooth the idle. Wait for another opinion before moving forward though. I'm sure someone has had the same problem.
 

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Is the check engine light on? Drive it for a day or two. Maybe even disconnect the battery to reset the PCM and drive it a bit and see what happens.
 

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If you run the codes you may be able to figure out what the problem is. I would bet O2 sensors, but the codes will pinpoint it better.
 

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Ya they can run it but they cannot reset it.
 
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