Some of the biggies for 94-95's that ping are:
Clean the MAF, check/clean/replace the ECT, check/clean/replace the IAT.
A lot of guys have luck with products like Seafoam.
And backing timing down/octane up, as mentioned, helps. The SN puter is load based and has issues with low load, low RPM pinging, even though you might not ping at WOT (it is a factory tune issue).
Good luck.