if you still might suspect the belt and /or tensioner did the 2008 have the upgraded tensioner... I have the service records for my 2006 that I got from the previous owner and one of them reads...customer complains of a vibration in the floorboard/pedal area....they put the upgrade tensioner on and maybe an idler....it fixed the problem, so the paperwork says...I believe it because I have never had the issue....just my own experience