97 c1500 5.7 starts then dies
 

alright so driving down the road last night, my engine just shut off. Everything else still worked but the engine wouldn't start.

so far I am able to get it to start but it dies right after. Pushing the gas has no affect on how long it runs. I jumped the fuel pump relay and it still did the same thing. The fuel pressure is 60 at prime. When it starts the fuel pressure slowly rises to 65 psi as the engine shuts off. And the pressure holds at 58 psi when cut off.

This truck does not have a pass lock system to my knowledge.

All fuses are good.

the spark is jumping the gap on a hei spark tester, but it's slightly purple.

Since the fuel pressure doesn't drop I'm assuming the filter etc is good.

one thing I did notice is that normally when you turn the key on to prime and cycle it off and on again the pump usually doesn't prime. But mine is, sometimes it will do a full prime each time the key is cycled, sometimes it's only a half prime. This is with back to back cycling once the prime cuts off. There are no leaks under the truck.
and the gauge still holds 60 psi.

another weird thing is sometims if it doesn't start, if I let it sit for a minute, or I bleed the fuel pressure gauge, it will fire right up, but still shuts off.

Two things:

Is your security light on? The car with a lock around it. If the light is on and stays on, chances are the security system has disabled fuel to the engine and you aren't going to get it to run no matter what you do until you fix the security system fault.

Also, where did you test for spark at? By the spark plug or on top of the ignition coil? I've sen it many times where the spark plug wire goes bad right from the coil to the distributor cap. You need to test for spark at the spark plug to verify spark plug wire, cap and rotor integrity.