I have recently become aware of some complaints relating to later model 2.7 4-cyl engines in Tacomas developing a knock. The accounts I read, say it sounds like a sort of deep knock during light acceleration at around 2000 rpm or so. The people expressed problems getting the dealer to replace the entire engine (they were just offered a short block). My 2.7 does not exhibit this problem but I was wondering if anyone else had heard of or experienced it. It is tough to get a straight answer from toyota service manager on this. I wonder if there is a TSB.