jrkn like fuel pressure loss

my 89 gta has 30k on it. i been havn probs fuel related. last fall i put new pump new assembly done everything right. Got it out today ran perfect then started jrkn everyonce in a while like loss of fuel. This cars like new all new flomastr exhaust etc. Any ideas i dont wanna take to shop unless i have to nevr seen rain so u kno theres not a mark. i wanna doit myself just dont kno what to look for..THANKS DAVE