98 Yukon Pinging

[HawkScot]

98 Yukon, 5.7, automatic, 144K miles, regular oil changes

 

I get pinging on lite acceleration, I did the Seafoam thing, didn't seem to make a difference. It has been doing it for awhile now, new plugs, K&N airfilter and no change. We've tried different brands of gas. We use premium in it when it is hot and it helps but it still pings occasionally, even on premium. I do not have a check engine lite on and would expect one if it was pinging and the computer could not adjust enough for it..?? Where are the knock sensor(s) on 98? maybe they are bad?

 

It doesn't ping all the time. We took it on a trip (8 hours drive) and it pinged some but not always. It is definately time to do something about it but don't trust the shops around here much (certainly not the dealers).

 

Suggestions are welcome, thanks in advance.