1992 Blazer wierd problem!

[Obiwan76]

My 92 blazer started dying a few weeks ago while driving. The blazer had a new crate engine (Vortec 4.3 cpi) put in it, only has about 40k on it. My first thought was ...fuel pump. So I change the pump strainer and filter. 2 days later it dies again.. Like all the other time it isnt starting back right away. I found that if I pull the coil wire off of the coil pack and crank it, it starts right up. Well I take it to my mechanic, he tests the fuel pressure and check it for codes. No error codes and he said fuel pressue is great. When I pul the coil wire off, the coil pack arcs and appears to be functionong properly. Well my mechanic has it for 2 weeks and he cannot figure out the problem. Anyone else ever run across anything like this?. Any suggestions on what to check, I will tell him.

[MT-2500]

Is the dist rotor turning and is rotor still at no 1 still at tdc compression
Is the spark going threw the dist to more than one spark plug?
What is the cranking fuel pressure?
Is it getting injector pulse?
Will it start on a shot of carb cleaner?

[Obiwan76]

Thats the wierd part, everything checks out. Timing, pulse, spark. I forgot to mention that it runs great no hesitation or power loss, then just dies. Once I pull the coil wire off and crank it over a few times, I replace the coil wire and it fires right up. It dialed in at 62psi at start, on fuel pressure. I am puzzled. My mechanic has worked on MANY of these and when i called him he said its probably an intake problem. After checking everything he has no idea what it is either. He did say he tried to start it the other day and it would not start until the coil wire was pulled and replaced. It was a cold start, had not been fired that day.

[MT-2500]

You need to test it when it does not start or dies.
Check for lose of spark or fuel or injector pulse?
Have you gave the old PC the tap/twist test?
Will it fire up with carb cleaner?