I went to advanced auto parts to check why my light was on and their tool said bank 1 and 2 engine running lean. Advanced said its not the o2's becuase the diagonostic tool would have specificly said o2sensors bad. They said it was becuase of the air temp. I dont believe that though. Ive got an 04 gt with just an offroad h pipe and drop in K&N. I used to have a programmer and ran 93 octance on it while it was installed. I sold it a few months ago becuase my car was pinging while the programmer was installed. After I sold it I ran 87 octane since. My car has pinged 3 times since I sold it. How can I fix this problem before something bad happens? Should I take it to the dealership first or would an xcal2 fix this?