In my 2007 Chevy Silverado 2500 (Latest model body style-gas 6 L engine), as I accelerate going up hill or anytime there is a load on the vehicle, the mid-range runs poorly. It runs like it is either starved for fuel or air and it performs poorly.

The dealer says "They are all like that." Seriously, I cannot believe GM would create such a poor running engine in a totally new vehicle. Or, if they have had a problem, I am not alone.

Any advice or tips would be appreciated.