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Q: Check engine light illuminated all the time. 2000 Mazda B4000

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Recently, the dashboard in my truck has started showing the check engine light illuminated and it doesn't turn off. I've had several repairs done, which include MAF sensor and oxygen sensors replacement, along with the gas cap change. The check engine light is still illuminated. Also, I've been getting a very low gas mileage. What might be causing the CEL to be on all the time and is there a way I could improve gas mileage?

A: Hello. If there is a misfire in multiple cy...

Hello. If there is a misfire in multiple cylinders of the engine, this will cause the Check Engine Light to come on. However, there are a lot of other reasons that the Check Engine Light could be on. It is important to retrieve the codes that have been stored by the PCM to properly diagnose the problem instead of blindly throwing new parts on. If the spark plugs are faulty, changing them may increase gas mileage. Using a premium gas can increase gas mileage as well. Have a certified technician, like one from YourMechanic, come and complete an inspection to determine why your Check Engine Light is on and help restore performance on the car.

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