I have a 2001 LS V8 that keeps throwing a code for a misfire on cylinder #7. I changed out all the coils and spark plugs, fuel filter, air filter, cleaned my MAF sensor and used fuel system cleaner. But for some reason I keep have this re-occuring code. Ive had others say it could be a bad injector or possibly a burnt valve? I honestly dont know what to do next....but I cant afford to go on a witch hunt trying to fix this issue. Any advice would be greatly appreciated, Thanks!!