[s-cars] RE: Knock sensor failure?

[Voits]

I, too, been struggling with a suspected knock sensor issue.  My car seems
to ping, although at times its hard to discern this noise from possible
transmission chatter, and my mechanic does not think it is, in fact,
pinging.  (sometimes I agree cause I can pull on the shift lever and change
the noise, but other times it presents differently, seemingly more from 'up
front', and louder more resounding in nature, and without the same ability
to influence with the gear lever)
We've pulled codes none except (0025500) abs dtc reference of some sort.
I've also had the knock sensors retorqued since this is the one
non-detectable condition; a bad sensor would show a code of some sort I
presume.  I pulled the plugs and they all look even and are a nice tan color
with no peppering.
So if there is a 'definitive' test of the knock sensor system I'd like to
know.  In the meanwhile I drive around a lot in 3rd gear when I would
usually use 4th so as to avoid the ping-like noise that is either my tranny
or is knocking.
Any comments welcomed.
Steve V.
95.5 S6, 60k miles no chip yet (till I sort this out)