Knock Sensor picking up rattles and vibrations?

Ok. I was just reading the new issue of performance in motion(from the store), there`s a section on fuel economy, and here`s the knock sensor article: "Get rid of strange noises! Our friends at Crane told us about the Chev pickup that lost 5 miles per gallon due to a rattling trailer hitch safety chain. It seems the noise traveled forward through the frame and was picked up by the engine knock sensor. The sensor, doing what it is supposed to, pulled all the timing out of the engine in an attempt to eliminate the detonation it was reading!" My question: If a chain rattling can do that, how about a performance muffler that is noisy and shakes(vibrations) as hell. How about a sub? Are they freaking out or the chevy truck is the problem? Anyone ever had experience with that? Thanks!!!

Knock sensors work on a very narrow frequency band. It just happened that this particular trailer hitch was sending vibration on that narow band. It's entirely possible, and must have been a bitch to troubleshoot!!!

But I wouldn't worry too much about it. For example, your subs emit a frequency way too low to interfere with your knock sensor.

That problem was one in a million (or at least several thousands!).

my knock sensors were "hearing" false knock from the loud exhaut and roller rockers. I had to use another knock module to filter out false knock.
Some engines can be very sensitive to noise.