Mine also "Pings" on reg. gas. It also has a bad case of Piston Slap on the real cold mornings, lifter/rocker "tic", etc., etc. I agree with Snake, if Premium settles it down, put premium in it.

 

Agreed with above on the top end is full of carbon. You can try using one fo the mentioned top end cleaners. If it doesn't smoke, you got alot of miles left on her

On a good note, it probably wasn't drove really hard at high rpm's(like most of ours' have ) if this is the case