2000 Chevy 3500 4door
Vortec 7.4 Gas (forgive me, I don't remember which digit is engine code.)
4x4 Auto trans
Air cond.

Just had engine replaced due to spun bearing on the crank. About 2 months before, it will spudder and misfire intermittently, throwing no codes whatsoever. I have tested the truck with the scanner during driving and in the shop.

My question is, how do I test the ignition module? I did a full tune-up, then rechecked everything, but problem still exists.

I replaced the Ignition Module ($108), and that cured my problem.

I replaced the Ignition Module ($108), and that cured my problem.

make sure the plug wires are of the proper resistance ...if the ignition wires are arcing this may have caused the module to fail/....the other reason would be very high miles....