Can you get the CEL code read at a place like Autozone? They'll do it for free.

Many over the years have reported an irregular and often wildly flucuating idle, jumps up really high sometimes. It's often the mode selector switch.
Did you notice any of the gear selector lights flashing weirdly?

Although I don't recall any saying they had to stand on the brake - but thought it's worth a mention.

Here's a thread (one of MANY) that talks a little about it, and what others have done and cleaned to fix/attempt fix.
http://www.vehicross.info/forums/sho...366#post244366

http://www.vehicross.info/forums/sho...39&postcount=3

Do a search on "high idle" and maybe some other key words, maybe you can find a thread or other mention of your type problem.

I'm sure some others will jump in here to give you some more suggestions.

good luck.