Next time it begins running rough try cycling the ignition off and back on.
Yes you can carefully do this while moving. If the conditions
 clears up for a short while then you need to look at a problem with the O2
sensor system. Wiring problems can be elusive. The wire can and crimp can
look good with the wire inside the insulation so bad it has high resistance.
The chassis reference for the O2 sensor is extremely critical. The ground
for the distributor hall sensor is shared with the O2 sensor. Many 87s have
that connected at the base of the plastic oil breather tower. Move it if
needed.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Steven Mills
Sent: Friday, September 11, 2015 11:37 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Rough Idle troubleshooting need

I will try to keep this as brief as possible. 87 Vanagon, stock 2.1.
intermittent rough run and loss of pwr. So far, have tested with good parts
ECM, AFM, Dist, plugs, plug wires, alternator, coil, fuel pressure/flow
rate, idle stabilizer, cold temp sensor, good fuel, fuel filter, fuel pump,
fuel injectors, O2 sensor, ohm'ed wires to and from all components. Have
done wiggle test on as many wires as we can get to or think of. Checked for
vacuum leaks. When running good, very smooth idle, warm-up cycle,
acceleration, etc . Never had one run better in my 25 yrs of owning one.
Just had about 6 days of 300 plus miles of driving without a hitch. When
rough, sometimes can be smooth for first 5-10 secs, then problems surface.
Most of time, when rough, rough from very beginning. Have worked alongside a
mechanic who has worked vanagons since the 80's, but we are both stumped.
Could use any and all  ideas/suggestions. Or someone to suggest in this
region of the country. Steven Mills,  Oklahoma