well in august i had my gsr motor built. 11.8 compression and so on. shad tuned it in september with 310cc injectors and hondata. its ran perfect since. well yesterday i noticed as i acelerated it started to "ping" not really loud but i could hear it with the radio off. so i went and got some gas (93 octane) and went home and checked my plugs, they were perfect. today when i drove it i noticed that if i ease into the throttle it pings in 2nd gear, 4th gear and 5th gear below 3500 rpms sometimes not always but if i floor it its fine. the car runs perfect just this pinging is making me nervous. any ideas on why all the sudden it started doing this? i havent touched the motor since it was tuned. maybe i need new plugs?