You've put the timing back to 10* and it is still pinging?
I guess I would make sure that you are running a high octane fuel, and double check your timing.
Maybe you've got a hotspot or something?
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White 1995 Mustang GT
Dynomax Cat-Back, Offroad H-pipe, ADS chip, K&N Filters w/o Air Silencer
My 1995 Mustang GT