Waltleon1

35 minutes ago, alex g said:

Never saw a copilot before. Maybe see what it's wired into and eliminate it if it's not necessary which I doubt it is. Is your turbo building boost that can definitely cause it to be sluggish

Yes the turbo is building boost, it has the power 1 and 2nd gear after that it really don't have the power to pull

16 minutes ago, fjh said:

which trans do you have?

it's just a Mack 6 speed 

I just bought a 1997 ch613 with the E350 with a 6 speed, drove it home bobtail and yes it was a little sluggish after 4 gear and on up. Got it home and hooked it to a 12000 lbs trailer and it don't have any power to pull it hardly. It's had a fresh oil change and fule filter change. But it does have a copilot thing on the dash I know nothing about. I Need some help on this one!?!?