This sensor sits on the front of the lower plenum next to the coolant temp sensor. Not sure what it is so hopefully someone might shed some light on this mystery.

Its the one with the black plug.

 

well after doing a little reading through the FSM and a little research online it turns out this is the cold start injector timer switch.

If the mods would like this thread can be removed but perhaps it is of benefit for YT to keep it.