First - she's got 222K on her, and while I joke that i can't kill her, she's getting to be a bit much (even though half of the stuff always ends up to be something small causing BIG issues)...

The engine surges a bit on start up and at idle. It is more prone to do this when it's wet out. This happened once back (moons ago) and it was resolved by cleaning the throttle body.

Here are my codes:
P101 - Mass or Air Flow, Circuit Range Performance
P0507 - Idle Air Control System RPM higher than expected
P0171 System too Lean Bank 1
P0174- System too lead bank 2...

and last - and I believe unrelated...
U0138 - Lost communication with All Terrain Response Module - (think this dates to a coffee incident, OR a bad ground... - my negative terminal end would night tighten-down - made the mistake of using a crimp down style replacement - and I don't believe its nearly as sound as a solder-style battery-end).

I threw a MAF sensor in it, cleaned throttle body, checked air box and filter... no results to speak of.

Any suggestions as to where to start?

Thanks, Gents.