motor sputters when i hit the gas

[whitepony91]

A few months back i had a new motor put in the car. afr heads, e303cam, edelbrock intake, 24lb injectors. also got a bigger fuel pump and adjustalbe fuel regulator, but dont remember how big the pump is.

anyways, the past few days, iv noticed that sometimes after i get up past about 3k rpm, the motor wont rev up, and it just sits there, pops a bit and sounds really dull, then its fine for a while and it will rev up. im thinkin its maybe a problem with fuel. cause the sound that the fuel pump makes sounds different. when it got put in, it was a low smooth sound, now its sort of a high pitch whine. But its only a few months old, dont see why a fuel pump would fail that fast. or maybe thats not it.. any suggestions on what it might be?

thanks