I have a 1995 blazer runs fine when the whether is cool but when it worms up it randomly backfires and loss of power when accelerating bad blew the muffler apart bad I've replaced the egr, tps,map,fuel pressure reg,cap,rotor,plugs,plug wires,coil still no change no codes the motor is vin. w model been to two different shops they couldnt find anything wrong?

 

check fuel pressure leak down, the lines to the spider (nut kit) can leak. Also the injector could go bad. Check ign timing, however I am unsure if it's adjustable on a 95. Double check firing order. If all else fails the only thing I could think of is the ign control module or it jumped timing

 

I would suggest checking (1) timing (2) fuel - air ratio (3) exhaust system leaks. Running Lean and exhaust back into the cylinder's are primary causes for backfiring.