We have a f350 dump with a 460 and a 5 speed. Iwe have put a lot of work into and we can't get it to run right. We have tried new plugs,wires,distributor,cap,ecm,02 sensor,iac,ignition coil,maf,tps and it xstill runs rough while driving. Idle is perfect it has the typical exhaust leak with the manifolds but were working on that. What is happening it feels like its missing afrer 20 min of drivin and then clears up around 2000 rpm, after 2000+ rpm it sounds and feels like it s breaking up. Sometimes it has a surgedwhere it clears up and runs fine for a few minutes and back to normal again. Can anybody help us before we make out work truck a piece of scrap. I feel like I own a race car after driving it ten miles and putting hours of work into it everytime


Thanks
Chris