Could this be a MAP sensor problem?

[john_p_50220]

I just bought a 1991 Firebird and just put in a fuel injector rail, all new injectors, and a new fuel pump. When I push on the gas to take off from a stop at a decent rate or try to accelerate faster there is a popping noise, it isnt loud like a backfire and you cant feel it. Could this be a MAP sensor or more? Only thing I can think of would be exhaust but I dont think thats the problem.