I have a 1995 Monaco Executive with a Cummins 8.3 mechanical 300 hp.
I just bought it and it had been sitting for about 3 years. I starts just find and idles fine but when I put it in gear and star to go, I have no power. I can never get the coach to go more than about 35 mph on flat ground. If I try to push on the accelerator to go faster it just gears down and this is in any gear. I would sure appreciate any help I can get.