"""OK, awhile back I posted about my van hesitating. If you remember I took it
to my mechanic who cranked the AFM screw to get it to run rich. The
hesitating went away, the van ran pretty good but I was down to 11 MPG."""

There you go, very simple... get a spare AFM and swap it! Like Scott said,
it's nice to have spare parts to do some test. Find a shop who as vanagon in
the yard / shop.  The embeded temp sender must be bad. You can check this one.

The only way to troubleshot FI is with good working / tested spare FI parts.

You save money and time, same fo the mechanic.

If the AFM mod did some major change, don't look further for now. Go back
where you started... at the AFM

If that doesn't work, write back. TB won't give you bad gas millage, bad
idle ok but no more. If with a different AFM you still have the same
problem, that should be change/check in order:

-Blue temp sender (change it)
-Check fuel pressure (that will eliminate a lots of parts / problem related
to fuel pressure)
-Unplug OS. (drive van)
-Distibutor (not cap-rotor)
-ECU

Cheers, Ben
http://www.benplace.com/