Eric,
    First thing I would check is the proper operation of the idle position
switch. With the engine off, stick your head over the engine compartment and
listen  as someone else presses and releases the gas pedal. You should hear
a switch clicking as the throttle body closes. If you hear it,  there is an
87.65743% chance that the switch is operating properly. You have to break
out the Bentley, an Ohm meter, two beers and the eye of a newt to be 100%
sure.

Let me know what you find.

Ken Lewis
http://neksiwel.20m.com/ a smattering of Vanagon related stuff