John Clavin ,
try to turn the big idle mixture screw out 1/2 turn .
I have done this to many vanagons that had the same problem and it cured
it 9 out of 10 times .
thanks Tony dba T.W. Engineering
'84 Vanagon
'55 bug
'65 bug
'66 fastback
'83 gti
'61 conv. bug