Engine light on after repair was done

I had a cracked cylinder in the engine mount of my 2001 Civic. I had that repaired along with having an oil change. About 2 weeks later, i noticed my gas mileage was about half of what it should be and my check engine light came on. I just checked the oil and it is slightly above the top level mark. Any ideas to what may be happening? Thank you.

Your mounts don’t have “cylinders” per se, they’re rubber mounts. No mount will drop gas mileage by 1/2. I think you need to go back to the shop and tell them what’s going on. It’s possible that they knocked a connector loose, like perhaps the temp sensor, while installing the new mount. That would kill your mileage.

Thank you for your input. I will ask them about this when I take the car back to them to see what went wrong.

take your car to autozone and get the codes read so you can find out what is really wrong with it. Do not go back to the same shop, because if they told you the engine mount cylinders were bad they are scamming you.