1991 Taurus Rev problem

Good Morning

I work with a fellow PhD who is having issues with this 91 taurus. The car is a 91, 3.0L V6 vulcon. He stopped the car then later came about about 10 mins later to leave and the car started and it rev'd very high. He proceeded to turn off the car, which would not respond and kept reving higher. (gas was not applied at all) Several attempts were made moving the keys to the off position, putting the car in D (would not move, transmission would not engage), or kicking the gas pedal (might be a stuck throttle). I believe that this is something to do with the lock cylinder/ingnition switch and the 2 rods that my be out of place and not making correct contact, thus not letting the car stop.

Odd thing was that later, he came back about 3 hours later and the car started like new, nothing wrong at all.This has happened 3 times, this being the third time. Twice it has occur when the vehcile is warm, and once when it was not.
I was thinking that it may be a TPS sensor that is getting stuck, or that something is losing contact when its warm

Any other ideas would be greatly appreiciated.

Dibsing
PhD Biochemistry Msc Pharmacology

The throttle in the '91 is all cable-driven. I'd suggest you start by making sure the cable is not binding and the throttle plate is not being held open. A stuck throttle plate would not explain why the car would not shut off though. Obviously those three times your friend was able to get the car to shut off. Assuming he didn't just let it run out of gas, what did he do to get it to finally shut off? Like you, I would suspect first the ignition swtich (not the key cylinder switch).

-Rod

Thank you for the quick reply.

He says that the first two times, he opened the hood to see what was going on and then closed/slammed the hood and the car stopped. The third time he kept moving the ignition switch on and off (in the column) and eventually it stopped.

I will be taking a look at it this afternoon to see what can be found. He started the vehicle up this morning and said it started and ran fine on the way to work.

My hypothesis is something electronic when the car is warm fails; the falling on the hood caused the electrical switch/ component to make contact and finish the shutdown.