Interesting question, Jon. I suppose if there is some slop in the belt teeth and cam sprocket, it might affect the spark timing somewhat. Enough to cause pinging...don't know. I rather doubt it.
You are supposed to change timing belts every 90k miles or 6 years, whichever comes first. Your '92 is a "non-interference" engine, so a snapped belt will not harm your motor. Just leave you stranded. With 245k on your engine, there could also be considerable carbon deposits on the head and piston which will exacerbate a pinging (predetonation) issue. If your timing belt has more than 90k miles, I would consider changing it out. Then you can let us know if it made a difference.
Thats good to know as ive always been gun shy when it came to cars with belts instead of chain,I might do a sea foam treatment just to do what i can to clear it up before going to the money jobs,thank you for the advice