A member here named Duke2.6 has had a lot to say about the TVS - throttle valve switch. I'll pass on some of what he's provided.
TVS -> 3 pole connector on the front/top of the intake manifold. Remove the air cleaner to get to it.
Now read what Duke2.6 had to say in this thread:
http://www.peachparts.com/shopforum/showthread.php?t=109866
There's a lot in the archives about the OVP. One simple test is to remove it and shake it. If you hear rattling, replace it. This device provides power to the idle controller. I'd be more inclined to think your OVP was OK if you were not stalling on a warm engine after some heat soak had set in and you've restarted and taken off, dying a short distance after starting. That sort of thing was described by one tech here as being classic OVP. I've seen this movie and a new OVP fixed it.
Some info on the throttle Microswitch at the next URL:
http://www.peachparts.com/shopforum/showthread.php?t=112136&highlight=microswitch