The first time I brought it in, they just chalked it up to "one of those things"... the symptoms lasted for a day then all was fine for a month of so. The second time it acted up for the duration of one trip (after the car was turned off, all was fine again). The third time I had had enough and brought it to a different dealer. At this time I had noticed that each time it acted up, it was either during a rain or a warm spring day when snow was melting... I was thinking water was the common thread. They were never able to say with 100% certainty what it was, but there was an enclosure that housed some chips/electronics that had a missing screw and some amount of moisture was in there. So they replaced the electronics/boards/chips/etc. even though their testing said the components were good. It's been a year and a half and I've had no problems since, so it would seem that it was the water.

I've encountered 'limp mode' before (though the 'limping' was inconsequential since the problem was a failed coil pack, so the car barely drove anyway), and this was definitely not it, like you guessed.

Unlikely, but not impossible. I had an issue where the gas pedal did nothing (to the floor or all the way up), but the car would slowly accelerate on it's own with absolutely no input, and the brakes would rev the engine (but not cause acceleration) when touched (though they would stop the car). Fun stuff. I was able to drive the car to the shop, but had to brake every twenty or seconds or so to counter the automatic acceleration (luckily they didn't overheat).

Third one's a charm! Been using dvorak for about 10 years, ripping to ogg ever since I started ripping my CD collection to disk.