Don't worry, it doesn't actually mean anything. The verb "bussare" in Italian can only mean to knock on a door. Autobusso doesn't mean anything, it could ever potentially mean "to knock on oneself" only if it was a door speaking. And even then it would sound strange and would be quite a stretch
Yeah, got it. I just got a bit confused because my mind went to one of the two absolute best V6s to ever grace our world (with the other being Alfredino Ferrari's V6)!