I was wonderin' the same thing. A dealer owned mine for about first year, then 2nd owner was almost 5 yrs, then sat at used car lot for a while, then me 12/08. My guess is, since mine was bone stock, PO had a shop tell him/her they needed it & replaced them with the cheap stuff. It spent it's entire life in Washington DC/VA area so do harsh winters cause need for more frequent tune ups?? I have no idea.![]()