OK....well it's been weeks and I have gotten no suggestions or responses that have helped....so I took it to the dealer.
I am by no means incapable as a mechanic, but I didn't do the basics. After a scan of the uly, the guy found that there was an error code relating to the motor that does the exhaust butterfly valve. He searched all over and found nothing obvious. Then he looked at the fuses...it was blown. He replaced the fuse and cleared the code.....nothing has returned yet.
So, for $60 you can get your fuse changed at the dealer, or you could ignore all the computer controlled crap and try not to think about sensors and stuff right away....and check the fuses.
Who would have thought, a check engine light for a blown fuse. BTW...this fuse is also horn and taillight, neither of which I have apparently had a use for in this time!