>| not sure whatto try next. Does the carbon canister have any bearing on
>| the vacuum? Previously a tube coming from the canister would make the
>| van run rough if it came off now it makes o difference on or off.

        If the engine runs no different with the plastic tube to the
carbon canister on or off, than it sounds like you have a vaccum leak
associated with that tube or the canister itself. You might pull it off
at the throttle body and check if covering the hole in the throttle
body changes anything... And also try disconnecting the O2 sensor
before starting the engine and hook a voltmeter up to the sensor to
get an idea of what the air stream down wind of the engine is composed of.
If the engine idles lower and the sensor is putting out lower than .5
volts, you have either an exhuast leak, a vaccum leak or the engine is
way out of CO adjustment... That is of course, my unexpert opinion, but
it just seems wrong that the idle would not be affected by introducing
a fairly substantial vaccuum leak...

dave