1993 Chevrolet Other

Engine Performance problem
1993 Other Chevrolet Models 6 cyl Two Wheel Drive Automatic

runs good when engine light is on but when light is off runs poorly and is also using alot of gas also has a little knocking sound
Walt sisne
June 4, 2010.

If the service light is on you are in open loop and have a sensor not working. That's why you aren' tgetting good fuel mileage. Get it checked out.

Jun 4, 2010.