It sounds like you may have multiple issues going on. At 210,000 miles and the apparent lack of good maintenance by the previous owners, it can be very difficult to accurately diagnose the problem(s) you may be dealing over the internet.
+1 to that!
You need a good ,thorough tune up not a rebuild. If you want to do it yourself just follow your FSM general maintenance guidance...
Plugs: pull/replace them and see how they look (try H8PVMNT's idea while youre at it)
Plug Wires: Replace
Distributor Cap/Rotor: Replace
Try to Tune the carb first not rebuild it...
Adjust idle speed/fast idle speed
Check choke system
Replace air filter and make sure intake piping is not blocked
Walk the vacuum/emissions system and make sure there are no leaks and all the EGR components work as intended.
Increased engine temps can also lead to things like detonation so check/flush your cooling system
a “pinging” sound in 22R can be several things other than pre-ignition caused by out of adjustment ignition timing.. Like heavily carboned combustion chamber, timing chain slapping against the timing cover, the fuel pump going out, exhaust leak, stuck valve, or valve lash out of adjustment.
Again +1. If none of the simple tune up steps fixes the issue then any of these things could be causing issues. Either have a mechanic take a look or start investigating them yourself.
