The throttle body can be dirty from residue of oil introduced upstream of it, like in the PCV hose as the posts about adding an oil catch can.
moist air can carry dirt and grime which will mess up the butterfly!
I strongly agree with your rodents dining on the wires, Donbrew.

 

Thanks again folks for the responses. UPDATE: Purchased rotors, discs, and calipers, as recommended by mechanic. Will arrive in about 10 days. Brakes will be done at that time and pedal sinking problem will be completely addressed. Hopefully not additional expense like a master cylinder. Brought it home last night from mechanics. Ran fine, no codes, "limp" mode no longer on. I'm thinking it was just from the lay up. In any event, I put fuel injector cleaner/stabilizer in the fifth of a tank of gas. Will try to burn off as much as I can (car not yet re-licensed) before filling with #91. I'll update on the brakes. Computers and codes can be helpful, but can also lead astray. Thanks again.