94 7.4L no spark

Help I was driving and all of a sudden lost power and back firing but would idil fine just no power got a code low voltage fuel relay changed out fuel pump
truck ran fine two weeks then did the same thing I was far from home went to a parts store got a new ecm and fuel pump relay but this time lost spark from coil ! will not start

Welcome to AF. TBI, I assume. Got 12v to coil, correct? Suspect module or pick up in dist.

I replaced the module now it runs but back firing from carb at higher rpm and seems to be missing the distrbuter shaft has no play in it!

Fouled plugs, cracked cap, switched wires, bad coil or wires, are some possibilities.