Nissan Repair: fuel problem, fuel pressure gauge, 1990 nissan 300zx

Question
I have a 1990 nissan 300zx, runs great except when the gas gets low, but not empty or when I put gas into the car. It runs up to 4,000 rpms, kicks hard into 2nd gear, runs up to 4,000 rpms again, then starts slowing down like it is losing power. If I put gas in it and let it sit for a couple of days, there is no problems. What could be causing this?

Answer
Mike,

A couple of things here could be the cause.  The first is the fuel pump is old and when you are low on gas the pump is not covered with fuel letting it overheat.  Second, the sock on the end of the fuel pump could be rotted and allowing trash from the bottom of the tank to get into the working end of the fuel pump plugging it partially.  I would get a fuel pressure gauge and check pressures when it does the surging thing.  That would validate my guess.  But, not seeing the car my thoughts run to a fuel pump replacement and the fuel filter as well.