Every time the truck is either at the top of 2nd or hittin 3rd the truck will sputter. It feels similar to the problem I had with my fuel pump going bad, but that was only when I accelerated. It seems to be worse going up or down hill so I think it might be injection issues. Truck is an 87 suburban 350tbi
Likely a fuel issue but also possible an ignition issue. What's your base timing with the weatherpack connector disconnected? When's the last time it got plugs, wires, cap, and rotor? You should do a fuel pressure test. Could be several things. Fuel pump is new so I'll assume the same for the strainer sock. What's the filter like? Nothing until the TBI, but they need rebuilding sometimes. The fuel pressure regulator diaphragms can go out, as can little seals and screens. What's the spray pattern look like on the injectors? Should be conical and consistent, not drippy or one weaker than the other. Sometimes they need to be cleaned or replaced. Do you have any check engine lights? I feel like a bad EGR or MAP would be more pronounced symptomatically. The computer would tell you if the sensors were picking up something strange in them. I'd check the base timing (6 degrees BTDC should do well), make sure the plug wires are tight on the plugs and the cap, inspect for vacuum leaks by looking for broken or disconnected lines using the emissions sticker as a reference, make sure you're good on the fuel filter, and I'd watch the injectors and consider doing a TBI rebuild, especially if it has high miles. I feel, though, that if you had an injector going out, you'd feel symptoms everywhere instead of in a concentrated area.
