My truck is stumbling (not an A-Body)

Fuel pump?

Not a new vehicle, but had a 383 Belv and it would do the same sort of thing to the point of stalling. If you put your foot down on it it would run fine and take off no problems. If you were just puttering around town it would try sputter every time you came to a light.

Replaced the fuel pump and fixed the problem.

Maybe fuel filter would help too. Bad gas perhaps?