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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.

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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