Turned out I had two problems, the failed idle control module and at least
one bad injector.  It was never quite right after the ICM replacement, and
then started dying at idle again, and also missed badly under load-it was
completely undriveable, and we barely got it back home after going to a
meet-up about 10 miles away.

So, I put in a new coil and all the related tune up stuff.  No change.
Checked the fuel pump pressure again and it was within specs, so I had the
injectors rebuilt and replaced the fuel lines, fuel pump, and filter while
waiting. The two injectors on the driver's side had never been touched
(being under the A/C compressor I understand why), and the hose on one
cracked and leaked when I loosened the injector holder. Seals were hard and
cracked, and the injectors looked terrible. I also cleaned up the throttle
body, adjusted the TPS, used a new seal, and did the capacitor fix in the
AFM just for good measure.

Installed the injectors yesterday (Rock Auto rebuilt, $25/each), and it runs
like a champ now with a lot more power!  I'm planning on it continuing this
way for a long time. But then it is a Vanagon. . .

Stuart