The Toyota throttle is not connected to the engine with a cable or linkage, it is wired to the computer by a sensor, the problem may be caused by reverse polarity through the throttle sensor circuit, from poor grounding from to many overlapping grounds, or from the to many over lapping power feed circuits, causing the throttle sensor to become an actuator, rather than a sensor, causing reverse energy through the throttle actuator, opening the throttle body instead of holding the throttle body closed.
Power feeding back through a ground, when power should be going to a ground.
(You can turn a starter into a generator, or a generator into a starter)
Toyota has always had to many over lapping ground and power feed circuits, causing reverse power surges, though off circuits, or circuits with no energy present, leaving a void for reverse energy to flow through, now add overlapping Bi-Directional electrical circuits to the systems with bad grounds.
It could be a problem in the cruise control circuit.
I have never inspected a Toyota with this problem.
When this happens, shift the transmission into neutral, Dial 911.
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Ask 911 to call the Toyota Bi-Polar throttle response emergency Hot line, then press 1 for throttle response problem on a Monday, press 2 for throttle response problem on a Tuesday, press 3 for no problems on any Wednesdays, press 4 to scream into phone on Thursdays after 3:00 PM, press 5 because press 4 will not work on Thursdays after 3:00PM or press 6 if your lucky enough to get to press 4, press 7 to return to press 4, press 8 to return to press 5, press 9 to talk to car computer, press 10 to yell at car computer, press 11 to talk to computer engineer, press 12 to yell at computer engineer, press 13 to speak to other drivers on hold, press 14 to donate money to Al Gores Save The Bi-Polar Bears emergency response Cold Hot Line, Press 15 to speak to a Human one last time, Hello, you have reached the Bi-Polar funeral home emergency response last chance to save Polar Bears Hot Line, press 1 to donate to save the Bi-Polar Bears, press 2 …….
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My Auto science teacher Allan Walter read this article and called to tell me of a similar problem on an anti-lock brake system on large semi trucks years ago, on one of the very first systems.
The anti-lock brake system would for no reason suddenly stop the truck.
The engineers could not find any problem, so they had the drivers of these trucks get out of the truck when this would happen, and then walk around the truck, and just take notice of everything around the truck.
The only thing they all had in common, police patrol cars nearby.
Turns out the problem was caused by two way radio-signal from police cars. That is a possibility for the Toyota throttle control problem. If so, as Allan said, is it a signal from a GPS or Cell phone or micro-waves or car radio or remote key-less starter or key-less door lock or garage door remote or T.V. remote or signals from space, or space aliens, if so, it will be awhile before it is diagnosed.
Thank You Allan