i have an 87 gta l98 just put headers on 3 inch cat and taylor wires and it was running strong then it started making a poping noise under acceleration now the poping is gone but it doesnt seem to be running right much slower and the exhaust isnt as loud any ideas on what could be wrong because I am fresh out of them checked the wires and no arching anywhere any help appericated thanks

 

define popping

 

when first starting acceleration it would sound like there was back pressure clearing out not a barkfire or a miss mechanic told me crappy muffler and 3inch crappy catco cat to 2.5 in cat back werent helping

 

Since you just changed your plug wires, I would start there. If you have the wires on wrong it would run poorly and may pop depending on how hard you get on it. Good luck.