The unfixable mystery problem

[carl johansson]

First place I would look is the throttle position sensor - but to tell you the truth I don't even know if the supra has that. Alot of high performance shope sell a bogus "power enhancer" that is a throttle position switch that tells the computer that you are at full throttle - when you are only at 3/4. doesn't really add power - the petal still goes full - just no gain after3/4 throttle.

This problem sounds like the switch is working backward for some crazy reason! Like I said - it's a shot in the dark - but if someone burned a performance chip and it got screwed up - this could be the issue!
AFAIK - The Rev limiter on this engine is burned on the ECU chip! ( we hit it on occasion in the lemons racecar!)

Carl Johansson