Ah the old throttle stuck on flat out trick. My mates wb kingswood does this. But the cause has yet to be found. I drove it home from Sydney in about 1991. I pulled out to overtake, floored it in third, got around the car in front, went to pull in and back off..... No back off. Just kept accelerating. Scared shit out of both of us. Pumped the throttle and it backed off thank Christ. My brother now owns this ute and it still does it. It's been on the dyno but never does it there for some reason. It's got the best blue 253 I have ever driven in it. Mild cam and 3:08 diff. It will pull 220km on its ear.