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Mike S.
Mike S., Chevy Mechanic
Category: Chevy
Satisfied Customers: 7433
Experience:  ASE Certified Master Technician
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99 silverdo. motor is running at 2500 rmp at idle. switched

Customer Question

99 silverdo. motor is running at 2500 rmp at idle. switched out TPS and the Idle air control valve but it's still running high. /would the PCM have something to do with this or the MAP SENSOR
Submitted: 1 year ago.
Category: Chevy
Expert:  Mike S. replied 1 year ago.

The first thing to ask yourself is the check engine light remaining on past bulb check?

Just because the TPS and/or the IAC was changed doesn't mean there couldn't still be a problem in the wiring or carbon buildup in the idle air passage.

Expert:  Mike S. replied 1 year ago.

It may even be a vacuum leak. here is a troubleshooting procedure for the IDLE CONTROL SYSTEM, I suggest you go through it and complete what steps you can.