In my 2000 (2500 4x4 6 speed 235hp 100k mi) at times I can be driving down the road and it will hardly get out of its own way, and then like a light switch, bang, its off and running good again. At times it wont even get over 50 mph on the freeway. The truck is stock except for the holley lift pump (which is putting out 9 psi at WOT). I changed the MAP sensor but the problem still exists. And seems to be getting worse. Any help would be GREATLY appreciated. Thanks guys
