Howdy guys, recently while driving my 4 cyl 2.9l 08 colorado 4-speed automatic with 53k miles, ive noticed what i think is detonation or pinging. it sounds like a quiet rattle or a small plastic bit flying around in the engine compartment when under load. i cleaned the maf sensor and the condition remained unchanged. thinking it might be carbon build up/dirty sensors, i then threw in some of shell’s premium gasoline along with royal purple max clean and after that a full tank of premium shell with cataclean. noise has stopped while i have the higher octane gas in the system, won’t know if it is “cured” until i fill up regular exxon gas i normally go with in the near future. but while truck was running on premium shell and the cleaner, i decided to do a italian tune up (just to prove to my lady friend the truck is capable) while cruising down the road. side note, my transmission always had sort of a harsher shift, even with good trans fluid, most noticeable on 1-2. now after the italian tune up the transmission 1-2 shifts almost seamlessly. i’m happy with that so far, and i was wondering if that was a sign the cleaner was actually cleaning? once again truck is still running on the tank or premium gas and cleaner, will throw in some regular gas after this last 1/4 tank. questions, comments, concerns, advice?