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Q: Car keeps stalling when I press on the brakes

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I have replaced water pump radiator and thermostat. Because it was overheating. Just to find out there was air in the system. I bled it. Now every time I put the brakes on it will stall. I just don't know what's going on. I'm confused.

My car has 205000 miles.
My car has an automatic transmission.

A: Your car has a unit in the fuel injection s...

Your car has a unit in the fuel injection system called an idle air control valve. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine. This valve is controlled by the vehicle's computer which will adjust idle speed based upon other measurements such as engine temperature, intake air temperature, and electrical system load or voltage.

When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed. This is all done by the idle air control valve. When the engine RPM drops below the normal range of 750-800 RPM (for most cars), this may indicate a dirty or faulty idle air control valve. In cases where this valve is dirty or failing, your vehicle will stall instead of slowing to an idle after the release of the throttle as you have described.

To avoid any unnecessary repairs, I would recommend having an expert from YourMechanic come to your location to diagnose your stalling issue and repair your idle air control valve as necessary.

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