One problem related to power train driveline has been reported for the 2006 Toyota Matrix. The most recently reported issues are listed below.
Purchased certified pre owned - (leased) 2006 Matrix 27940 miles 7/26/08 - on 11/12/08 32955 miles after oil change dealer wrote : "tires are wearing funny - aligned at n/c did not rotate rht rear cupping - 3/25/09 oil change 38632 - dealer wrote - rotate tires if needed - last time in had tire wear issue needs tires has 1 good tire on car on lf. Apparently this is a problem with Toyota - haven't contacted dealer yet but will after reading complaints. I don't know if the after market shim fix will void my extended warranty or not. . . . . .