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Q: Engine hesitating during startup

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I have an issue with the car hesitating and stumbling a bit on the startup. The engine can be started fine during cold weather, at 40 degrees F and under. The issue happens when the engine is around 450 RPM, and it starts hesitating and stumbling for a moment. The car would be fine again after a couple of seconds, when it's at 1250-1500 RPMs. What could cause this? Is this normal? Thanks.

A: Hello. It is not normal for your engine to ...

Hello. It is not normal for your engine to be at 450 RPMs. This could be an indication that there is a loose or disconnected vacuum line or a vacuum leak from the intake. It is also possible that there is a problem with the mass airflow sensor, idle air control valve, or throttle position sensor. If these sensors are faulty the check engine light will usually come on. Have a certified technician, like one from YourMechanic, inspect your vehicle in order to pinpoint why your engine is hesitating at low RPMs.

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