skullivan64

Oh, also the air filter is not plugged because I dont have it on at the moment and I've checked the air flow meter components and done resistance checks on it as well. As far as I can tell, no problems with AFM.

There is no pinging but when I push the throttle it will rev up extremely slow (if at all) and it will make poping noises like its backfireing but the poping comes from the intake, not the exhaust. I should probably check pressures with a gauge, I just haven't gotten around to it yet... another thing to mention, even though the pump is brand new it is very loud (humming that changes with voltage) like it can't keep up with the pressure needed. And when I say that I pinch that return line and build the pressure back up, it runs exactly like it should be running. Responsive to throttle with no hesitation, no backfire, very clean sounding. Thats why I'm thinking its solely a pressure issue but I'm not positive

Ok, so I have a 1975 280z 2+2 that runs but not well. I have replaces the fuel pump, FPR, and the fuel filter and am running 91 octane with some octane additive. When I'm pushing the throttle it has a huge hesitation in reving up but if I pinch the fuel return line and give it throttle it runs like a champ, no problem at all. I'm stumped... can anyone help me?? Thanks