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Howard Duncan
Howard Duncan, ASE Certified Technician
Category: Chevy
Satisfied Customers: 389
Experience:  Over 20 Years experience in all makes and models; owner of Duncan's Mobile Automotive, LLC for 7 yrs
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88 Corsica: revving..went o3k rpm..Idle air Control Valve..old one

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I have an 88 Corsica that is revving too high at idle. It has gone up and down at times, but it just went o3K rpm and now is over 4k...Could this be the Idle air Control Valve and is there a way to test the old one before buying this $100. part to find out it doesn't solve the problem?
here's a thought...Is it possible that the injector is stuck open and feeding too much fuel? I know that they have to pulse, but is that possible to stick open and still operate?
Hello, I can tell you a cheap way to get this fixed. I had a chevy that was doing the same thing I did everything in the world to this car and it still persisted. I finally took the IAC out and adjusted it to where the car idled good and I left it disconnected. It doesn't hurt anything and is a lot cheaper that fixing it. If you don't like this answer I will opt out I am just trying to help you out as cheaply as possible to get your car back on the road. Make sure and check the pin on the throttle shaft that contacts the TPS they were famous for shearing off and the tps just floats around. Also, make sure when you throttle up the tps lever is in constant contact with the pin in the throttle shaft. I hope this helps I can opt out if you are not happy with my answer. Please click accept if you are happy with this answer, if not, please don't leave negative feedback I will help you more just ask. Regards Howard
Customer: replied 7 years ago.
Thank you for your input Howard. It's getting late tonight, I will have to look at the car tomorrow and get back to you. As far as taking the IAC out and adjusting it, you mean to push it in and disconnect the connector before starting it. See how it runs and move the pintle in or out until I get the desired idle? Is that what you mean? And am I right in the purpose for the IAC is to regulate the idle when a load is put on the motor?
Well you need to turn the pintle it actually screws out to adjust it towards the hole in the throttle body. Just adjust it until it makes the car idle right. You may have to play with it to get it right. Thanks
Howard Duncan and 7 other Chevy Specialists are ready to help you
Customer: replied 7 years ago.
Good Morning Howard,
   I went out this morning, took the IAC out, pulled the pintle out a ways and reinstalled the IAC without plugging the electrical connector back in. When I started the car it ran beautifully...!!! Not sure if this will effect the way it runs when it turns to colder weather, but for now I'm happy and I know what part needs to be replaced when the time comes.
   Thank you for your prompt and accurate help Howard.

So happy for you :) I wish you the best; have a great day!!!!
God Bless,