One thing not mentioned are the  injectors.  Just replace them with $20 rebuilt ones available from several sources, including Rock Auto.  Worked for me.

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Kevin Duvernay
Sent: Wednesday, March 25, 2015 11:52 AM
To: vanagon@GERRY.VANAGON.COM
Subject: RPMs constant, but pulsing vibration at idle

All,

2.1 '87 westy with AC, manual

I'm experiencing a slight pulsing vibration at idle. As soon as I get off idle it goes away and the engine is smooth as can be. The pulsing does not appear to be related to rpm fluctuations as the rpms seem to be holding perfectly constant at around 825. The pulsing seems to occur about twice a second. I can feel the pulsing through the seat and also the vibrations when it pulses are enough to make things in the cabinets buzz, so I can hear it. However, from the outside the engine sounds steady as can be.

Just looking for any ideas as to what this could be to help with my trouble shooting. These are the relevant things that I have recently replaced with no effect:

idle control valve
idle control module
throttle body
throttle switch
vacuum lines/hoses
checked for intake leaks, none
motor mounts
transmission mount
02 sensor
temp 2 sensor
all three belts

Thanks