My present 2003 Silverado is paid for, runs like a top with 175K on it, is incredibly comfortable to drive and has enough power with the 6.0L engine to do whatever I need it to do. But it gets 9 mpg in town and 12 on the highway. And the resale on it is almost exactly what I paid for it used 3 years ago.
Bob
Bob,
My buddy with the '02 six liter (2500HD 4X4 with extended cab, eight foot box, 4L85-E tranny, and 4.10 gears) took his into the dealership soon after he bought it new, looking to get the advertised power and fuel mileage. (And to get rid of that annoying detonation like sound which habitually comes from that engine)
They attempted a couple times to cure his complaints via reprogramming of the engine tuning.
When he went into the dealership for the third time, they promised to FIX it. He drove it for a couple weeks and was amazed. Better power. less annoying knock like sounds from the engine, and much better mileage.
He went back to the shop and asked what they had done.
The shop manager winked at him and told him he now had a Cadillac Escalade engine in his truck, via a simple computer tune.
He has gotten 17 mpg ever since and he was running 80 mph on the freeway 70 miles per day. Of course, the mileage drops a bit when he hooks three to five ton of trailer to the back bumper. But not to the levels you quote for an empty truck around town.
An engine computer tune might well be worth investigating.
