I just bought my '78 280z and from day one it has had a bizarre problem.

The car starts fine, and has no problem idling. You can hear the engine stammer every once and a while during idle, but it is not enough to cause any problems with the engine running.

When you accelerate at low RPM the car lurches. If you raise the RPMs to around 2500 or so before releasing the clutch it does ok.

Many times when you are shifting the car backfires right at the low end of the RPMs. Just as you are raising the clutch you will hear it *POP*.

One day the car would just not run for me. If I raised the RPMs to above about 2000, the engine would just shut off, and it would do the same if I put the engine under any kind of load. As soon as I lifted my foot off the gas petal the car started running again. This problem went away as mysteriously as it came, I can only guess that it is related to the other problem.

The car has a new cap, rotor, spark plugs, plug wires, fuel pump, and a refurbished air flow meter. The guy before me was obviously chasing this problem.

Any ideas? I'm stumped.

I would put a FP guage after the fuel filter and confirm proper pressure. Also be aware that even if pressure is ok, it could be a supply issue...IOW, crud could be clogging the tank outlet.