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Q: Idle speed control value

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Idle speed control valve is making it lose power
My car has an automatic transmission.

A: Hi, thanks for writing in. I’d be happy to ...

Hi, thanks for writing in. I’d be happy to help.

This is a case of an idle air control valve not working properly. An idle air control valve literally bypasses air around a closed throttle plate inside the throttle body so the engine can get air at idle. On start-up, the engine control module (ECM) or powertrain control module (PCM) checks engine coolant temperature, ambient air temperature, barometric pressure (on some engines) and then determines how much air and gas is required to start the engine.

The idle air control valve works at idle and during deceleration-- in other words, any time you take your foot off the pedal. During deceleration, the computers on most fuel injected vehicles perform a “fuel cut” procedure where the fuel injectors are forced to cut fuel to the engine resulting in RPM drop. However, since the pistons are still moving up and down, the engine still needs an air supply. The idle air control valve opens during deceleration to provide that air. This appears to be the problem you are experiencing. If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect and diagnose this issue for you, and make any repairs as needed.

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