I had the same problem with my 85' GL until I replaced my idle control unit. Actually I didn't even have one, someone had just plugged the 2 plugs together instead of replacing. When I put it in haven't had any of those problems since. It's like a $10 part from the Bus Depot.
I'd also check the O2 sensor
have fun,
Tracy
85' GL "Ripple"
 Tyler Bradford <pdx_vanagon@ATTBI.COM> wrote:Hello, all. I'm a newbie here to the mailing list and a new Vanagon owner as
well. I have a question that I was hoping to get some help with. I have an 85
Vanagon GL w/a rebuilt engine that is giving me some idle troubles. The problem
occurs when stopped or when the clutch is in and the engine has had a chance to
rev all the way down, even if still moving. What will happen is that the RPM
will go waaaaaaay down, to about 200 or so, and almost stall out, to the point
where the console lights are flickering. then it will seem to catch and rev
back up, up to about 800-1400 rpm. As soon as it tops out, though, it will fall
back down to 200, and the same thing will happen again. This doesn't happen
every time I am stopped, but probably about 70-80% of the time. Also, sometimes
the engine will stall completely when turning a corner w/ the clutch in. I have
tried bypassing the idle regulator (? little black box to left of engine) to no
avail. I have also replaced the air filter recently. Any input would be greatly
appreciated. Thanks.