1985 300zx

Need help car set up for about yearit would start but would not take gas so i clean out the cat and it will still start sometimes takes gas sometimes want .They told me my gas was bad I filled car up put in seafoam stills run the same want take gas cleaned MAF and switched ecu with my 1986 300zx still no change .I change fuel filter will start an idle soon as you give it gas it try`s to cut off and there is a noise coming from air filter like a tea pot boiling and I have KN air filter there is white smoke coming from exhaust some times and a bad gas smell .