Another good guess but, if the throttle plate was, indeed, sticking then the car would accelerate at an easily detectable (and seemingly intentional) rate of speed. To have the plate sticking open enough to rev to 4K (or even 5K as this user is stating) would be the same as pressing the gas pedal until your car accelerated to 5K (Depending on the gear, that would be some rather moderate speeds, there.)
I am not saying that TH can't make the car accelerate (as it has and does in mine every once in a while) but it isn't anything that would make you freak out... We're talking about 1 or maybe 2mph in 3rd or higher.. perhaps 2-3 in 1st or second gear. TH is not directly controlling the throttle plate, or acceleration, just simply "affecting" your idle.
Ray
