my wife's truck is an 08 Silverado crew cab 2wd. 5.3 engine.
we have been getting around 16 sometimes on a good day 17.
which isn't as advertised but we were happy with it. Engine light came on and we took to dealer about 3 wks ago. The fixed an exhaust vent valve for free and light went off said it was no big deal. Ever since that visit we are luck to get 13.8 mpg and that was on the hwy. City driving has dropped to just under 13 mpg. i called dealer they said they did no reprogramming on the computer.
Can anyone offer any insight into this mystery? I have run injectory cleaner thru it regularly, especially since this started.

 

what no reply's? am i the only one who's ever encountered this problem?

 

try to get the dealer to reset the ECM

 

cassieaaron, I would like to direct message you about this issue if I may. Thank you for your time.

Jeff Morris, Chevrolet Customer Service

 

took to dealer today. They changed air filter and said nothing was wrong with it.
I had just changed the air filter 6000 miles ago so i know it wasn't the air filter. I guess im stuck with this thing at 14 mpg. No wonder everyone has turned to Toyota.

 

Toyota ... I think not .... I have a NBS 2007 reg. cab long bed 4.8L and 4x4 Z71 with dual exhaust and tonneau cover and in town I get about 15-17 and on the hwy with the cruise set at about 70-72 I can get 20-21mpg .... just as good as the wife's Trailblazer at 20mpg... So I am not sure on your problem .... but I would keep my chevy any day over a toyota