My dad has a 96' 4x4 5spd and it runs great except for every now and again it stalls and misses like it is starving for fuel I have changed the overflow valve cleaned the pre filter changed the fuel filter.Any other ideas? gonna try changeing fuel lines this weekend don't know where else to look

Stumped!!!!!!!!!!!

 

It's probably the fuel lines. When it does this, is the fuel tank low? Some have had problems with the pickup in the tank.
The other possibility is the pre-heater. Search and read up on those problems.