Well for the longest time the o'l Bronco [96 5.8 E40D] has had a pinging problem that has slowly gotten worse. Full tune up, decarbonizing, checked cats,premium fuel, etc,etc. A friend of mine with a 99 Mustang Cobra said that some folks on that forum had had the same trouble after fifty or sixty thousand miles and changed their 02 sensors despite no MIL light or codes.
All I can say is wow!!!!.....it isn't even the same truck, not only does it not ping, but overall drives remarkably better. Part throttle accerlation, the way the trans shifts, hard accleration...you name it.
I rember back in the day [80's-90's] they used to say change your 02's every 50,000 or soo. Perhaps it isn't a bad idea. Oh and by the way it fixed my buddies 99 Cobra also of the same problem....pretty cool!!!!!!