We live on a farm so the fact there is rodents is no surprise. However strangest thing is the knock sensor harness has been chewed completely off two times in last two months.. when this happens it causes power loss. With the extra shielding the wire has tells me it gives off a low frequency that would irritate most animals and me at this point since the part is never available. If it actually gives off a frequency, it is absolutely unnecessary and a complete nuisance.