i will fill up the gas tank on monday and by wednesday its on a quarter of a tank. what causes this?
Asked by roderick_williams_18... Sep 20, 2014 at 05:26 PM about the 2006 GMC Envoy Denali
Question type: Maintenance & Repair
5 Answers
Do you have a CEL light on the dashboard? The place to start is the emission system, like the O2 sensors.
Best Answer
Mark helpful
roderick_williams_18... answered 10 years ago
Which o2 sensor would it be the upstream or downstream
Change them all at the same time. In my experience if one go's your other ones are not far away from failing and you'll be back under the vehicle again.
BTW. Don't use the universal O2 sensors. They are crap! Use the same kind that came out of it.