Assuming that Toyota are using "fly by wire" throttles one would expect it to be a fault with the throttle position sensor which could tell the ecu that the throttle is fully depressed when in fact it has returned to the closed position?
On a slightly different, but related subject, we used to have a Saab 93 turbo diesel.
My wife mistakenly over-filled the engine with oil. Normally you would think that was not a big deal? Wrong. After about forty mins driving, oil pressure built up to a level where the turbo started to suck the oil from the engine causing the engine to scream at well above full revs. At this point, the engine was running on the oil, not the fuel! I was driving at the time, and will never forget sitting at the side of the road, ignition off, keys in hand, while the engine screamed like a banshee! It took a few minutes of repeatedly depressing and releasing the clutch with the car in gear, to eventually get the thing to stall.
Needless to say, we sold it shortly after
