last night on the way home i had a loud engine backfire that shut the car off and would not restart.i recently built the engine about 3000 miles ago so i replaced timing set and had zero problems.it almost sounds like it jumped time but i would like to start simple and work my way to that.i had a chevy truck do the same thing and i thought it jumped time but it was a bad ignition module

 

so its turning over but not starting correct? did the backfire come from the exhaust or engine compartment? could be the opti or icm,,, scan for codes and sorry but,,,, probly better do a compression test on all the cylinders.

 

yea the backfire came out of the tail pipe

 

check shbox, has tests for the opti and other things in the how to section. 4th Gen LT1 F-Body Tech Aids