My '02 Z28 a4 car has a little preignition when launched from idle (not stall) Only a clack or two. I am pretty sure it is not detonation as additional octane does not help and it will not do it under far worse load conditions. It will also on occasion do it when cruising in overdrive at 45 MPH and then stepping on it a little. Once it shifts down it is fine. It will not do it if you are in drive. My car has only 8000 miles on it.

 

I guess my question is; what should I do ?

 

Get/Find someone with auto tap so you can check it out