I was sitting in a quite parking lot last night with the engine running, I had my radio on. I random bass noise coming from the right side that was inconsistant with the music, so I turned off the radio. But then I heard the bass sounding noise again. I thought, maybe someone has their radio up in the far distant with the windows down.. I get out and I don't hear anything, so I turn the engine on again and I hear the noise again. Its not a loud bass noise, but it's not a sharp pinging noise either. Its not frequent either... maybe 1 or 2 knocks every 10 seconds... when I reved up I hear the noise alittle more frequently Remember I was idle, not moving...
I'm trying to rule out if its engine knocking or a tranny bearing... What exactly does an engine knock sound like? Is it a loud ping noise or a more deep bass sounding noise?