10 mpg with new Jasper engine & transmission
Asked by 1993gmc2016 May 02, 2016 at 06:15 PM about the 2001 GMC Sierra 2500HD 2 Dr SL 4WD Standard Cab LB HD
Question type: Maintenance & Repair
1993 GMC Sierra runs rich. ALL components new and I mean everything, Jasper 5.7 engine and transmission. I have talked to several full time mechanics and nobody has an answer?????
3 Answers
Did the O2 sensors get plugged back in during engine replacement? Is the check engine light on?
1993gmc2016 answered 8 years ago
Bob, I've been dealing with this problem for some time and swapped 3 sensors... I wish an engine light would come on so I could get a little closer to finding the answer. Expecting to keep the truck till the end of time I went all out with engine, transmission and ALL components, again everything! Six other mechanics have had their hands on this thing without success.
I know the spark plugs are new, but have you pulled them to see what the coloring looks like? Does the engine feel like it is running at full power?