Alright, I think i found the problem with my 260z in 5th gear over 3500RPM (Popping through the carb/backfiring through the carb).
Alright, so after a shitload of troubleshooting, trying to figure out why it was backfiring through the carb, i think i have it nailed down, i tried a different electronic fuel pump the other day, and now i can get it upto about 4000-4200 before she continues to backfire, does anyone know of a good fuel pump thats good for about 6-8PSI (for carbs) or any High volume, but not High Pressure fuel pump? I'd prefer to stay with an electric one (as manual pumps suck).
Any ideas?
thanks
.cre

 

yeah, i already pulled my carbs apart, checked the needles, checked the bowls, etc. and they were all ok, i was running it fairly rich to get it to perform right, but im tired of pushing gas at low RPM, plus to get the popping to go away, it would be VERY rich at low rpm.

 

hrmm.. I'm not 100% sure, I'll have to check when i go home tonight. Thanks for the tip
.cre

 

yeh i checked it out, on the carb near Cyl #1, there is a plug on the top next to the gas line (gas line is furthest to the front of the engine), and the plug is in the slot next to it (closer to the rear of the engine). The only reason i think its the Fuel Pump, is that with the time i've noticed that it got better was with a higher flow pump (well, a newer pump). so im hoping that increasing the flow a bit more, may get rid of the popping out of my carbs at high rpm in 5th gear.
.cre