Question Asked: check engine light goes on and off
October 25, 2009, 11:02 AM
For the last three years the check engine light has been going on and off. When it first started coming on it would run rough then run fine when it went off. Now when the check engine light comes on it runs fine and rough when it goes off. I've had a diagnostic test done four times and it is not tripping any codes. Also the car is only doing this when it gets to running temperature. This car has always had scheduled maintenance done and has never been neglected. The mechanics are stumped as to why this is happening. Any ideas?