I'm guessing 35 inch tires were the culprit on mine. On some hills, the engine would rev over 5K just to maintain 45 MPH.It does great! All stock aside from airbags. It's still a mini-truck towing a TT so there is definitely some expectation management, but I don't have any complaints. Hills and flats at altitude takes rpms, but that's not any different than towing ~10K with my Hemi.