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Old January 6th, 2012, 14:49
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Engine idle problems after engine rebuild (extremely high)

Ok so having an issue after getting my motor back in after a rebuild on my 01 sport auto 4x4. As soon as i crank it up it will spit and sputter for a couple seconds then the motor suddenly revs up beyond 4000rpm and i have to shut it down for fear it will go higher and damage my newly rebuilt motor which isn't even broken in yet.

I have double checked and the throttle body isn't moving like the gas pedal is being pressed when this happens and i have just finished taking the idle speed stepper out and cleaning it with no change. I only see the 3 vacuum lines that plug into the side of the intake as well as the one vacuum line that goes from the valve cover to the intake but all the rubber boots seem to be in good condition.

Should i do a computer reset? Any other ideas for me to try??
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Old January 6th, 2012, 15:13
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Re: Engine idle problems after engine rebuild (extremely high)

Most common reason is a intake manifold that isn't seated correctly or a mangled intake gasket.
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Old January 6th, 2012, 16:22
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Re: Engine idle problems after engine rebuild (extremely high)

make sure all connections are good, i mean like take hoses off and check both sides, sometimes cracks and failures are hiding in the dark little corners where you least expect them. also check out your throttle position sensor, i know that if they get moisture in them they start acting up, also ive seen a couple tps units that just fail, and of course when they do the computer doesnt know the correct throttle position and it will try to keep the engine idling by doing things like revving up.
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Old January 6th, 2012, 17:46
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Re: Engine idle problems after engine rebuild (extremely high)

Quote:
Originally Posted by old_man View Post
Most common reason is a intake manifold that isn't seated correctly or a mangled intake gasket.
This.

Double check your intake manifold; I'm guessing it didn't seat correctly.
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