unintended...

[C1J1Miller at aol.com]

Sounds like your cruise control lever got stuck.  There was a technical 
service bulletin for the V8 related to this (same setup)... the retainer for 
the cruise control rod breaks, and the rod jams the throttle wide open.

Next time this happens to someone, use the brakes to control engine/vehicle 
speed (in gear!), quickly find a place to pull over, and shut off the car, 
but keep the key to "on" so the steering wheel won't lock up.

The fix involves a new round washer retainer piece.
Chris