ok, i have been having a problem for a lil while now and i have no idea why. when i gun the car at full throttle my car gets a pinging detonating sounds. i have just installed 4 new o2 sensors in the car to see if it would help but it hasnt. the fuel filter was changed not all that long ago. the current mods i have are in my signature. i get the pinging problem when i have an 87 octane tune on the car, the only time it stops is if i use 93 octane gas with the 87 octane tune. when i put the 91 octane tune on the car it pings even with 93 octane gas. i took the tune off completely and even stock the car pings unless i use 93 octane gas. any ideas?