1999 Oldsmobile Alero GL 6 Cyl 3.4L
Why is my car getting terrible fuel mileage?
I recently replace the spark plugs. They are all properly gapped, and the wires are good, but for some reason the car has been backfiring and getting terrible fuel mileage.
The vehicle will need to test by a full function professional shop grade scan tool capable of reading grams per second and calculated loads in order to detect any bad or margins sensors.