I HAVE A 1994 FORD F150, 4.9 LTR, PUICK UP, 2WD, THAT WILL NOT START UP UNLESS YOU SPAY STARTING FLUID INTO THE INTAKE.

Probably not. If the sensor was causing it not to start, then it would not start even with starter fluid. This points to a fuel issue. Have the fuel pressure checked. It might be low.

Straight into the intake n/s/f grill or take inlet off on air box don't spray too much though

You first need to find out why it will not start, so no generic answer is of any use. Does it have fuel pressure? Spary starting fluid into the engine air intake, does it start and stall? If yes then the fuel pump may be defective. If the fuel pressure is ok then check for fault codes as this engine is computer controlled, to do this follow the link. Get Ford OBD1 Trouble Codes in Under 10 Minutes

I'm following another issue like this on a 1996 Jimmy.
This engine requires 60psi or more fuel pressure to run.
You need to have someone check the fuel pressure at the rail- throttle body with a gauge.

basics,,,air,,fuel,,spark,,compression,,timing,,,pull a few plugs,,smell them for fuel,,if dry,,,take snorkel off throttle body,, open throttle body or flap half way,,spay a little starting fluid or injector spay into throttle put the snorkel back on see if motor fires up,,if so then ck fuel delivery & pressure,,,,hope it helped

could be a couple of things first check for spark then fuel the easy way to check if its getting fuel o r not spay some starting fluid in the throttle body and try starting it

does it run rough after warm up??or cold too,,u mite have a vacuum leak,,,take some injection cleaner spay,,carb or brake cleaner spray,,seen many different spays used,,,but spay around air intake,,around base,,see if engine will stumble,,also seen temp censer problems,,where its tell the ecu that the motors cold,so it rich-ens the fuel,,injector,,hoped it helped,,

check the feul pump pressure if not enough it will do that you can take a spay bottle and spay the intake with gas as it runs and if
it stays running change the feul pump if not you have a coil problem

sounds like the fuel line has gotten too close to the hot exhaust manifold - and you are building up pressure to the intake, then you hit a (heat created) bubble - and the engine dies.

Check the fuel line from the intake down to just below the engine bottom... if you see it too close to the exhaust heat - move it or insulate it with heat tape (Autozone, Pepboys)

Sounds like a vaccuum, or gasket leak. Easiest way to diagnose is to get a can of starting fluid and spay it around any vacuum hoses and intake area while it's running. Be careful! Starting fluid is extremely flammable!

If you notice an acceleration, or de-celeration while spraying the starting fluid, you should be able to pinpoint the leak.