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Q: I have an EFI engine and when I start the engine I get a missing sound - I've checked everything cannot find the problem.

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My car have a missing sound ( like a humming sound ) am not finding the fault???

My car has 120686 miles.
My car has an automatic transmission.

Hello and thank you for contacting YourMechanic. If the sound is a loud chirping sound that only occurs when you start the engine and makes the engine bog down then it goes away, then there is nothing wrong with the engine. This is the alternator bearing seizing up and then breaking free when it gets hot. I recommend replacing the alternator and the drive belt that controls it. This sound is very common on the Corolla models. If you need further assistance diagnosing your vehicle, then seek out a professional, such as one from YourMechanic, to help you with the start up sound.

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