01 2500hd chevy -- when towing toy haller (25ft) engine cuts out at 65-70mph. Does this every time i tow the camper, doesn't matter where. went to west virgina, and tennessee and had this problem all the time -- when driving at around 60 gas pedal gets real firm and if i push it more engine cuts out and goes to idle until i slow down quite a bit or restart. -- truck has hypertec programmer , extra fuel filter kit and stright through exhaust-- and runs great without trailer -- but as soon as i hook it up it wont go over 65 --- any thoughts as to why would be great --- thanks
