1996 GMC 2500 Suburban
7.4 liter, V-8 Gasoline
When going uphill, as the rpm’s drop to around 2000, just before downshifting, the engine will begin cutting out. It jerks and loses power. Forcing a downshift to increase rpm will usually stop the jerking, although recently it was in first gear, high rpm, and was still cutting out. This cutting out problem became apparent shortly after I purchased the vehicle with 68k miles on it.
I’ve replace spark plugs, air filter, and fuel filter. I’ve tried higher grades of gasoline.
Overall, the engine does not seem to have the power that a 454 should. It slows significantly on average hills, of course, get horrendous fuel mileage (11-12 mpg).