Problem 1 So i was going down the interstate 1990 hatck "stock" engine with headers cat resonator and magna flow sounds great until my car backfires out the intake then all of a sudden quiet no more exaust sound.
Problim 2 So sometimes my car just wont start no matter if it's cold hot nothing and when it dose it runs ruff can here it missing after 1 to 30 seconds just shuts off I cant figure it out. As for the engine goes bored and stroked was a d15 now like a d 19.5 10:1 compression fully balanced crank spinning to a healthy 7500 rpm no problim Ebay head (dont know brand) built at Sher performance
. Please help as this is my daily driver
new parts; pluges wires starter alternator radiator (way to big never gets above 180) haven't replaced whole dizzy just ignitor

 

welcome to the forum. check to see if the timing belt has not slipped a tooth. check the icu for proper operation. check for proper fuel flow. if you have a fuel rail, check for proper pressure.

 

Problem 1 sounds like the spark on a cylinder did not light up.
Unburnt fuel went into the hot exhaust and popped. Backfires.

Had this happen to a mustang.
It was the little roll pin on the distributor gear.
Pin sheared and timing went to hell. A backfire and then dead..
Sometimes the pin would stick and it would start for a second then shut down just as quick

 

. I have put it straight up on cam side and tried every dot on my flywheel and have also set dizzy

 

It backfired through the intake side

 

This is all guessing, ...
You have a different problem.
Backfire on intake side sounds like the engine timing is off
Did you check the timing belt?
Open valve cover and see if cranking engine moves the valves
If not then broken timing belt. I don't know.
Good luck to you. Hope it is a simple and cheap fix

 

It backfired through the intake side. Good luck to you. Hope it is a simple and cheap fix

 

It does sound like Timeing belt is broken.