I'm back from the dealer. Originally, he said it would take half an hour but it didn't work out that way. The guy who wrote up the work order wrote "fuel gauge" instead of "fuel economy gauge" so the tech spent half an hour trying to diagnose a fully functional fuel level gauge. After he figures this out, I tell him I have parts waiting for me so check with the parts department; the issue is with the tachometer gauge control module. The part is actually a CD. The tech has to open up part of the dashboard, connect the TGCM to a computer, then run the CD. The CD had a different version number on it, but the guy tells me that this is the latest and greatest version. The reprogramming took 4 or 5 tries before it completed (the first few just didn't go - I'm hoping it was issues with the PC and not the car computer). The whole deal took about 2 hours Now I'm not yet past 62 miles so I don't know if this cured everything.

And yes, the main odometer does get reset, but they reprogrammed it to the correct mileage.