I just put in my GSR motor and I know the TPS is bad in it I am replacing that tomorrow, that's causing some power loss and backfiring i know but theres another noise my motor is making which im not sure what it is, it sounds like a cd spinning n scraping something but theres no cd in the cd player lol i even disconnected it to make sure its no doubt coming from the engine i have no idea what the scratching sound could be can anyone give me some advice as to what i can do?? maybe valves r making that noise do i need to adjust them or something