Fuel system short

My 1993 5.7 buick roadmaster wagon has been stalling, sometimes it would start right back up and other times it would have to sit for anywhere between 5 to 90 minuets when it refuses to start the gas gauge would bounce around, I have replaced distributor brand new complete, idle air flow motor as it also had an idle problem which fixed that problem, replaced fuel filter and the next day it stalled once after about 3 miles and started right back up drove about 10 miles to work it sat there for 10 hours started right up drove it about 2-3 miles it stalled again and would not start but this time gas gauge is buried on full, please help me, what do I need to check and how do I test it? Im assuming its shorted out somewhere? Thank you