1992 Tioga Montara 18 M rig --fuel issue
i am not a mechanic- just enough to get into trouble- usually not enough to get out of it.
I have recently inherited a 1992 Tioga Montara 18M rig. It has low mileage- about 70K but runs very ragged. I have tried fuel treatments- about ten tanks of various brands Sea Foam, STP, Motorcraft etc... I have replaced the fuel filter (a friend with a shop and proper tools replaced it) and it still runs ragged- works in low idle but as I try to attempt highway speeds it starves out or acts like it has a governor that is malfunctioning.
Any suggestions here? it seems pretty decent besides this fuel problem- which is especially bad climbing hills- (and paint)
i am thinking maybe the fuel pump- but have no way of testing that or knowing where it is- visible inspection doesn't reveal location... does anyone know about this model? Is it in the tank? it is the 7.5L 460 engine in an E350 chassis.
I believe that it is an early model fuel injected engine and so don't dare play with the supply lines which are probably pressurized.