Check Engine Light On? Here’s 5 Reasons Why
1) The most common problem when your check engine light comes on is your oxygen sensor has gone bad. The oxygen sensor or 02 sensor is responsible for monitoring the amount of unburned oxygen in the exhaust and let’s your vehicles computer know when there is not enough or to much fuel. So what does this mean? To replace a bad 02 sensor usually cost about $200.00, but ignoring it will give you a 35% reduction in your gas mileage.
2) The next reason your check engine light can come on is if you have a loose, damaged or missing gas cap. It can be as simple as tightening the gas cap or replacing it for just a few dollars. If you ignore the problem you will see a 0.7% decrease in your gas mileage.
3) Up for number 3 is your catalytic converter. Usually the catalytic converter will have a reason for failing. To have it fail on its own is very rare. It is usually a related part in the system that will cause it to fail such as a bad spark plug that has been ignored and should be replaced. This is why it is so important to take care of the small problems before they turn into more costly problems. To fix a catalytic converter will run well over $900.00 to repair.
4) Next is the MAF sensor or Mass Air Flow Sensor. The MAF sensors job is to regulate the amount of air coming into your engine and calculating how much fuel should be going to the motor. When this part is not working correctly it will be responsible for lowering your gas mileage by as much as 15% to 25%. To replace the MAF sensor runs about $400.00 to fix.
5) Last but not least is the spark plug. The spark plugs in your car are responsible for igniting your cylinders in your motor by igniting the air fuel mixture. When a spark plug goes bad it creates a misfire which can melt or even destroy your catalytic converter, and give you bad gas mileage.