1996 S10, 4.3L, 152k, Engine started pinging under moderate acceleration on 1996 Chevrolet S10

No Check Engine Light. Have replaced wires and plugs. Chilton's Manual says that there are no adjustments with this particular ignition system.

Asked by for the 1996 Chevrolet S10
could be an egr valve. too much temp in the cylinders. could also be a carbon build up as well. what kind of fuel do you use?? many possibilities.

I switched to 89 octane, but that made no discernible difference. Also it pings as soon as I start it and drive away while the engine is still cold.