ok i posted a couple of weeks ago about me doing a tune up wires.acdelco plugs and dist. and msd coil. pace setters long tube headers i extended the o2 wires with a peace of regular black wire and now the car backfires at idle randomly sometimes it wont for 5min other times it will do it 5 times in a row i checked the fireing order 5 times i am 100 percent shore it is correct no crossed wires

 

usually a back fire is because unused gas gets into the cats

 

Maybe its runnin rich? Check the fuel/air ratio.

 

no cats im thinking the same about the air/fuel

 

Thats what i would check. If the firing orders correct then ignition isnt the problem unless some how the timings way off. Im new to these lt1's and anything with all these modern sensors and electronics haha, but I've seen lots of cars backfire when runnin really rich. My dads friends nova had the timing 180 degrees backwards and it backfired like a son of gun he said. was when they were kids of course.

 

you just installed the Pacesetters, correct?

Your O2's are shot and need to be replaced

EDIT- that's why I sprung for the whopping $20 and bought O2 extensions instead of making my own. I can replace O2's on the end of my Pacesetters in a matter of minutes.

 

yes i just installed the headers and im buying and installing new 02 in the morning