Thanks to all the listers who have helped me try to solve my "pinging" problem.
Here are a few more New To Corolla's questions:
Is the water pump on my 1989 1.6L Carb Corolla driven by the Timing Belt?
Was my car originally delivered with red raditor fluid back in 1989? It now has the green stuff and I was wondering how important it is to switch over to the red stuff?
The whole exhaust system on my car is pretty well shot. The car has only 42,0000 orignial miles (little old lady car for real) and it sat and just ran to the church and back. Should I buy a factory Toyota exhaust? I found a receipt in the glovebox from Midas for a full exhaust system she had installed when the car was 13 yrs old with 14,000 miles on it. The rotted muffler system is (I believe) a Midas system.