Broken throttle return spring = WOT. Is there really only one?!?
 

While doing a warm up test drive after changing my oil yesterday, I felt a pop in the gas pedal as I accelerated, and the car suddenly took off. Pushed in the clutch and it raced to redline. I pulled over and studied the car for a while on the side of the road and found a broken throttle return spring at the throttle body. I was able to limp home by rigging up a tie to hold the throttle shut and let the car idle the rest of the way back home.

After examining the system and searching PP, it looks like the SC's were fitted with only one throttle return spring, while almost every other 911 has at least two. Is that correct? That seems to be a pretty dangerous set up if so. First of all to only have one spring, and second of all to have the failure mode being wide open throttle!

Any suggestions on where to place a safety backup so that this doesn't happen again? I am now terrified that it's going to happen to me at the track while apexing through a turn and cause me to go flying into a tree!

should have one vertical up above and one horizontal under the intake.

It appears as though I'm missing the horizontal one under the intake then. Well, now I'm missing both since the other broke. Any pictures of that one handy? I didn't see it on the parts diagram on PP.

you can put one inside the other

911.110.165.02
Spring part number will let you locate on the pet. Connects between the bottom side of #2 runner and the accelerator console.
Bruce