[cory]

someone told me you get worse mpg with the check engine light is on, whether or not something is wrong with it. true?

 

[wwbmopar]

If there is nothing wrong it shouldn't change your mileage. It would depend on the reason for the light.

 

[petrock]

The check engine light can mean alot of things ranging from the Oxygen Sensor manfunction, or the PCM itself is messed up (happened to me). I would take it to a dealer and have them check it out...

It could have an even worse effect then just bad gas milage...

Good luck...