My 1984 Toyota pickup, 22R engine, pings every time I go uphill in the canyon I live in. Anything over about 1/3rd to 1/2 throttle will give me a lot of pinging. I can normally make it up the canyon in 4th gear at about 1/2-3/4 throttle and 35 mph, but to stop the pinging I go down to 3rd gear and drop the speed a bit.

I recently replaced the vac advance, the retard side was dead...and the timing is set according to the FSM, and total advance is around 30 degrees. The pinging is the same before and after replacing the vacuum advance. I also just cleaned out a plugged accelerator pump nozzle...no difference in pinging even though acceleration is a bit stronger.

Where else can I look...EGR system? Any suggestions?

jc