Whats the fuel pressure? how many miles are on the injectors? Have the injectors been replaced? Is the EGR still functional? When the pinging occurs can you ease down more on the throttle but the engine seems to not pick up any power? Or does it seem to have more and ping less with less throttle?
Mine had this issue, I replaced the stock injectors with Venom units, reset the fuel pressure and it made a big difference.

 

tbi rebuilt by affordable fuel injection injectors were rebuilt and tested. tried two fuel pumps. i agree has to be a lean condition now what??? egr gone block off plate no vacuum leaks egr taking off of chip tune

 

not an expert but i thought the egr acctually fends off detonation by cooling the cylinders a little im not sure that was the best thing to do with removing the egr

 

not an expert but i thought the egr acctually fends off detonation by cooling the cylinders a little im not sure that was the best thing to do with removing the egr

EGR is actually used to lower NOx emissions, it does fight detonation/spark knock, but that isn't its sole purpose..