1991 Chevy Camaro

I Have a 1991 chevy camaro rs I just replace the spark plugs and gas filter and air filter and the pvc valve I also clean the iac senor I also check the plugs wires there where good. MY Question is that My car would pop though the intake and it would sputter. But it only does it once inwhile when you floor it it will clear out couild it be the fule injector sticking or the filter on the bottom of the injector. When you let sit for 1 hour it would run great.