Wonder if anyone can help me out on this ...

Lately, I've been experiencing engine pings ONLY under hard acceleration PAST 4,000 rpm. It doesn't happens below 4,000 rpm, whatever the load. Mechanic has checked ignition timing and its right on the dot. Tried retarding the ignition timing and the problem still persists. Checked CO as well and its within specs. Have not made any changes recently except for a change to a set of Bosch Platinum +4 plugs. Whats happening???

Get rid of the platinum plugs as soon as you can. They were not designed for this engine..go back to the copper ones h7dco! The poor spark that these platinum plugs produce cannot be handled by the 103 and 102 engines (no variable timing for starters). Everybody wants a modern solution for their cars but this is one situation where the old way is much much better!

Do a search on this forum you will get some more info. Hope this helps.