Earlier this summer I had it working perfectly.  Now, when I try to engage and have my foot on the gas, i feel it "catch" but when i release my foot, the speed slowly drifts down.

There does not appear to be any leaks, and the vac canister was replaced in the summer(that was when it worked great)

The Bentley is sorta worthless on testing of this system........I am just glad it worked on my recent 2000 mile vacation trip!

Any ideas or tests i could do?

Adam P                              
81  Westy "The Brick "
70 Single Cab "Whitey" 
74 Beetle "Ol Yeller"
73 Transporter (STILL at paint shop)
1988 Vanagon Wolfsburg 
75 Campmobile "for sale'
Used Vanagon Parts for sale (mostly aircooled)