As a followup to a problem I've been bugging the brickboard for awhile with, I recieved my replacement AMM in the mail today and plugged it in, reconnected the battery, and the car fired right up and idled properly. I drove it to work today with no problems - actually, because of all of the other stuff I chased the problem with, the car runs really, really smooth. Thanks to everyone that contributed!

Here's the short version:

Car suddenly wouldn't idle. If you held the gas, it would eventually idle, but idled poorly. CEL tripped eventually with code 1-1-3, 2-3-1, and 2-2-1.
Eventually, once the car adapted, it would idle, albeit poorly. Hesitation on acceleration. Ran fine at part/full throttle.

Tested AMM using voltage checks - checked out fine.
Pulled intake manifold, replaced ECT, cleaned EVERYTHING in the intake, pulled fuel injectors for pro cleaning, cleaned throttle body, swapped out spare IAC. No change.
Tested fuel pumps - in tank pump bad - replaced. No change.
Checked/cleaned ground points - no change.
Replaced AMM with spare - car runs perfectly.

Thanks again!

Here are the relevant threads:

http://www.brickboard.com/RWD/volvo/1364080/220/240/260/280/installed_new_amm_88_240_still_dies_right_starting.html

http://www.brickboard.com/RWD/volvo/1362742/220/240/260/280/making_slow_progress_rough_running_still_interested_art.html

http://www.brickboard.com/RWD/volvo/1326578/220/240/260/280/91_240_wont_idle_cel_113_fast.html