I got home and parked my car in the garage (i never park in the garage always outside) and today as i got out i heard this humming coming from the b-pipe at least it sounded like the b-pipe, it would hummm then stop, then hummm again then stop again and finally it went away. has anybody else have this happen to them or should i be worried??? maybe this has always happened i just never noticed

 

I think, not sure but mine does that too, it is the electronic engine mounts.