My local dealer told me yesterday that there is a shortage of the additive used to make 0w20 oil and won't be getting anymore till February. They've never lied to me yet so I went and bought some synthetic 5w-20 as I'm overdue. The oil light came on twice yesterday as I slowed down and went into autostop. Also, my mileage really sucks. Not sure how long I dare drive it like this, but FYI, next time, I'll just go to the dealer I don't trust as much or call a Toyota dealer to buy some oil.