About the rough idle: I struggled with this for years on my 1.9. In the end
it wasn't one silver bullet that fixed it. Replacing the engine mounts
helped. The rebuilt AFM helped too, once I had it calibrated by a
professional Vanagon shop. Another thing that surprisingly helped was
tightening the alternator, AC, and PS belts. Mine ran fine at higher speeds
but drove me nuts at the stop sign. Now it's pretty good.