Right on psfred! I once purchased an off-lease vehicle that required premium unleaded, and shortly after owning it the check engine light came on. The car ran fine, but I brought it to the dealer to have it checked out and they discovered that one valve was dead and the others looked pretty lousy. The tech offered that the previous owner didn't use premium. Thankfully the work was covered under warranty, otherwise it would have been a $2,000 lesson on why you should pay the extra pennies at the pump. Of course, the lessee didn't care.
2004 E320 Wagon
1998 Range Rover 4.0 SE