My 98 Protege ES has recently started "pinging". I started putting premium unleaded gas in which has helped a little bit but
completely. Any suggestions???

 

Try changing your spark plugs and wires. If you have a distrbuter, get your engine tuned up. Also try some fuel system cleaner. Switching to higher octane gas solved the pinging for a little while for me, but then the carbon buildup in the engine made the pining come back for me.