Help!

My vanagon had a new engine put in about 6 weeks ago after I threw a
rod.  It hasn't run right since.  Idle speed was really low when I first
picked it up, but I thought it was just an adjustment that I needed to
get it back to the shop for.  Well, then when I turned the A/C on for
the first time all hell broke loose as I wrote you guys and gals
before.  RPMs went all over the place, revving very high and refusing to
die, even when the ignition was turned off.  My thanks to all the list
members who took the time to explain the ICV and ISM to me and to point
me in the right drection.

Took it back to the shop.  They found a loose wire between the Idle
Stabilizer Module and the engine and supposedly fixed the problem.  On
the way home it did the revving thing again twice and wouldn't allow me
to turn it off.  Took it back to the shop.  They can't duplicate the
problem so don't know what the fix is.  Both days that I had such
problems were 90 degree days and I had run the A/C, we haven't had such
weather since, could this be an issue?  I still don't have any trust
that this issue is resolved.

So now, I noticed that it's running rich and rough.  Took it back to the
shop, they checked the O2 sensor, the ECU, the AFM and who knows
whatall.  They found that it was running on 3 cylinders.  After
disconnecting and reconnecting and moving things around and checking the
compression a couple of times, they told me they don't know what they
did, but that the problem is fixed and the compression is at 120 on all
four.

My husband picked it up last night and says that on the way home that
the RPMs would go so low that the oil light would come on.  I drove it
today and don't see any of that, although it seems to be running loudly
and somewhat unevenly.

What is going on?  Anybody know?  Failing that, does anybody have a shop
that they feel is knowledgable and trustworthy in the DC/Northern
Virginia area?  I thought I had both, but I'm beginning to wonder.

Thanks,
Karen