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Q: Car dying when stopping

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After letting my car idle for about 45 minutes one night, I took off and it began dying at every red light. Managed to get it home by basically restarting and gunning the engine until taking off. The next day i started her up and had no issues. A few days later I let my car idle for about 30 minutes, and the same thing happened. Got it to walmart, shopped for a bit, came out and got all the way home without any issues. What causes this? My first thought was fuel pump, but why does it only do this after a long period of idling and never gives me a hint of an issue otherwise?

My car has 141000 miles.
My car has an automatic transmission.

Hi There! It sounds like you may have a dirty or failing idle air control valve causing your engine idle to fluctuate and eventually stall. The idle air control valve is a small valve on the engine’s intake system that reads the air intake as it comes into the motor. This is controlled by the car’s ECM which uses this information to make adjustments to the air/fuel ratio depending on various inputs such as outside air temperature, intake air temperature, load and various other things. As you accelerate, your car’s engine is receiving a much higher dose of fuel than when at idle and conversely, when you let off the gas pedal, there is a sudden change in this fuel supply as a result of your foot letting off the pedal. When this happens, the job of the idle air control valve is to bring this deceleration down to a slow and smooth idle rather than suddenly cutting off the fuel supply causing the motor to die. When the idle air control valve is not working properly, this cause a disruption in this process resulting in the engine not being able to idle properly. I would recommend having a professional come to your location to diagnose and inspect your vehicle.

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