Well I was practicing a really quick launch after work today. Stalled it at 3 grand and let it rip I shifted out of first to 2nd at like 5400, i take 2nd up to 5400 into 3rd and BOOOOOM I hear this loud ass backfire. The car runs perfect though, but what would cause it to do that? The timing is fine, I run 93 in it. I just ran some lucasoil fuel treatment a week earlier and it seemed to be doing fine all last night. Any ideas?