Greg, if your car ran ok last year, but this year you have pinging -
maybe slightly colder plugs would help, along with the octane improvers mentioned. Because you have a GEN-I and there is the looming head gasket issues, inspect your plugs closely - also check for signs of head gasket leakage. Make sure your coolant system has not degraded, or you might even
consider the 99 fan upgrade. Beyond that, if all else fails, do what Larry
suggests about pulling some of the ignition advance. Pinging can be a symptom
of other motor problems, and if left untreated, can destroy your motor.