Hopefully I will find some help here. I have a good friend that owns a 2001 Chevy 3500HD Crew Cab 4x4 with the Dmax in it. When he first bought it a year ago he was getting 16.5 mpg. It has progressively went down to 11.5 mpg. I told him to check the restrictor guage for the air filter, it was in the red. Ok no-brainer...wrong. The air filter was replaced, still no change in fuel economy. No trouble codes stored. He recently recieved a recall notice about his fuel injectors, he went to his local dealer and they checked it out. They told him there was nothing wrong with it and sent him on his way.


Any ideas?

Ok if he didn't bother changing the air filter, has he changed the fuel filter..how about the Allison filter?

yeah i got an idea....the injectors have probably gone south on him by now...mine did the same thing then all of the sudden most of the fule was going past the rings and into the crankcase, good luck tell your friend too bad

I am taking an oil sample and sending it in for analysis. I also put him in contact with some people I know at the GM customer service center, they are directing him to a another dealership to have the recall addressed that involves the fuel injectors. He also thought his warranty had expired, he did not know that the 5yr/100,000 on the powertrain carried over to him as the second owner. I will keep everyone posted on the outcome.