Extremely lean idle, very rich at high revs
 

This has happened a couple times before and it usually fixes itself in a bit, but this time it's been going for over 24 hours and I'm starting to think it's sticking around.

At idle my AFR is very lean, north of 16.7, and sometimes pegs the wideband at 19+. If it does idle, it's very rough and I have to try to keep my foot on it so it won't die. Weird thing is, the more revs I build, the richer it gets. By 2.5-3k it hits 14.7 and at redline it's pegged rich.

I'm assuming if it were a clogged or busted injector or filter it wouldn't get richer at higher revs. At this point, I'm thinking it's a sensor. I'm new to the whole fuel injected thing though, so I'm not sure what I'm doing. So, where should I start?

What sensor being busted would result in lean idle with the it getting richer with revs while coming and going a few times before now?