We’ve just purchased a 2011 Chevy Silverado 1500 2wd extended cab with vortec 5.3L V8 6-speed automatic transmission. It’s advertised to get 21/15 mpg and we’re only getting 11-12.
We’ve taken it back to the dealer who says there’s no problem. We haven’t had any check engine lights.
Has anyone had a similar problem? Any suggestions?