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Q: Check engine light comes on when fuel gauge drops to 1/4 tank or lower.

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Hello, my check engine comes on when fuel drops to a 1/4 tank or lower and vehicles runs rough, but when tank is filled light goes out and car runs better. I haD a scan done at Autozone and it showed misfire on cylinders1 thru 6.

A: Hi there, thanks for writing in. It sounds...

Hi there, thanks for writing in.

It sounds like your car is experiencing misfires due to low fuel. Even though your tank reads 1/4 full, the fuel level sender may be incorrect. This could be compounded by the fact that having the tank under 1/4 full, the fuel could slosh away from the fuel pump inlet point and cause it to starve for fuel. If the car runs totally fine with a full tank, my suggestion for the short term would be to just keep the tank over 1/4 full, which is good practice anyway. The fuel pump is inside the tank on your car, and relies on being submerged in fuel to stay cool. When the tank is constantly run low, the pump can overheat and have a reduced service light. The long term solution would be to have the check engine light diagnosed and the fuel level sender accuracy checked by a qualified professional, such as one from YourMechanic.

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