Question One: Thought the clutch was slipping (noticed this twice). Nothing unusual now for a week. Could this still be a bad clutch?; In other words, will this happen slowly (slipping) over time? Or will a clutch just begin slipping and then the whole process goes quickly, which means replacing with a new clutch almost right away?
Question two: 154,00 miles: So could I use, say, STP oil treatment? Now I know Toyota doesn't recommend this. But, could STP oil treatment
really hurt the car? Couldn't it help to maintain good lubrication. What really could be the danger? I would add it at every new oil change.