It starts & then immediatly shuts off..... but will keep running if i spray ether into the carb not a plugged injector, not a fuel pump, and the rails are getting fuel

Take it to a mechanic

It's definitely a fuel problem but not necessarily the pump. An old trick (but isn't perfect) to check the pump is to bang, gently, on the fuel tank while someone is cranking the engine. If the engine starts, it's the fuel pump, however, if it doesn't start, it doesn't prove anything. You'll have to check to see if power is going to the pump. Another thing to check is to make sure the injectors are pulsing by testing them with a noid light. If the injectors are not pulsing this indicates that there is a computer related problem and you might need to use a scanner. BTW, I wouldn't use ether for testing as this could cause a blown head gasket. We usually use spray carb cleaner, as this is not quite as powerful.

This is fairly normal for cars left standing for lengthy periods, u can start most vehicles by spraying fuel directly into carb, or a great product called Bradex in the air intake, this is an ether in a can, once the engine starts it should run, but some vehicles that r started this way to often, get to start only this way, it sounds like despite new pump, the fuel is draining back over night & not there for starting in the morning, check ur fuel lines I bet its 1 of them causing the drain back, fit a 1 way valve as close to the carb/injector system as possible

Probably fuel pressure issue. Check for leaks, dirty filter, low fuel pressure could indicate bad fuel pump. Normally, a float would cause flooding, but a clogged jet could cause a lean / no start issue. Try some gumout fuel cleaner and a gumout spray clean of the carb and linkages before you get to far into a part issue.

possibly bad fuel pump. Check fuses first.

Fuel filter?..or vac acctivated fuel regulator..check w/ vac pump...is new pump running do you hear it relay clicking ????

are your injectors being fired by the computer.remove one of the injector connectors and using a low impedance test light or a small dash light bulb check for pulse or blinking light while cranking.

Check the fuel pressure at the Shredder Valve, You should have 60PSI to 65PSI upon start and should drop about 5PSI when running. If your fuel pressure is good then it may be a bad injector system. The fuel injector spider system that the vortec has are know to go bad, from the fuel pressure regulator to the puppet fuel valves. Change the fuel filter first if it has not been changed yet and have the fuel pressure check. Good luck and keep me posed. Note: it's been know that spraying ether to start the vortec with the spider injector system has got the puppet valves to catch fire and melt the ends of the puppet valve leading to the replacement to the whole system. Good luck and keep me posted, be glad to help.

if this is a 1980 F150, emissionwiz is correct in saying it has a carburetor, if your engine runs on ether, you do not have fuel supply to the engine. Check fuel delivery at the front of carburetor, should be a line screwed into the carb, may be connected by a rubber hose, remove this line and crank engine, look to see fuel is gushing out of the line, if no fuel the pump is bad, check fuel lines back to pump for leaks, replace leaking lines if necessary. If you get fuel then your float inside the carb is stuck, and the carb will need some attention, hope this helps, let me know

Best do a fuel pressure test. Should have chg. fuel filter from the get go. The only other filter is on the end of the fuel pump in tank. Bad gas and dirty gas will plug up fuel filter, hense burn pump up.