Nissan Repair: 93 Altima missing, nissan altima, fuel gauge

Question
I have a '93 Nissan Altima with 130k miles.  It sat for a couple of years and I just got it running about three weeks ago.  It ran rough to start with and I added fuel injector cleaner to the tank and changed the spark plugs.  The initial roughness is gone, but now at times the car idles roughly and will not accelerate.  At about 2k rpm the engine misses intermittently (it sounds like "wump, wump, wump, wump).  If you back off the accelerator it will smooth out.  It only runs smoothly in the 1500-2100 range.  I have noticed that when I fill the tank, this problem always occurs as I leave the station.  It continues this regularly, but not constantly, for the first 80-100 miles.  Then it runs great for about 100 miles.  Then it starts again.  The fuel gauge shows empty at about a half a tank, so I have to fill it up again to make sure I'm not actually out of gas.  What do I check next?

Answer
Bradley,

The fuel gauge float in the tank is in need of replacement.  The fuel pump might be your problem so check the fuel pressure at the fuel rail.  I would also replace the fuel filter soon.  The pump will have to come out of the tank to get to the sending unit for the gauge and if the pump is acting up this would be a good time to replace it.