94 chevy k1500 5.7 Symptoms 1. starts only 3 to 4 times in a row (on off)then just crank. will not restart after being ran for a min or two, but when started you can drive it and stays running, shut it off and restart just cranks. If I wait a couple of min it will restart. Symptom 2. When starting the truck with the timing wire plugged in it will start but sounds like it running on 2 cylinders shakes and wants to die, but if I unplug the timing wire from under the glove compartment it runs and idles fine with a slit misfire and giving a lot of throttle to it will make it combust in the throttle body. There is a check engine light that comes on codes 42 and 54. 42 to is Ignition control module (ICM) – electronic spark timing (EST)/ignition control (IC)/bypass circuit malfunction. That's from not having the timing wire plug in. 54 is Fuel pump circuit – voltage low.

Replaced/ 2 fuel relays, fuel filter, fuel pump, oil switch, temp sensor on top of manifold, idler air control, both throttle body injectors, did a node check with test lights works fine, fuel regulator/gaskets, pickup coil, ignition control module, spark plugs gaped at .35 it does have a msd muti spart AL6, 8366 msd distributor, and a blaster 2 coil.
I have a spare truck that runs great,same year and motor that I swapped ecu and chip, map sensor, and even stock coil eliminating the msd muti spark box, and still no change