Gary, your cat can disintegrate if the fuel mixture is too rich for an extended period. When it disintegrates, it tend to plug up the muffler and impair engine performance. To clear the debris, the cat and muffler have to be removed and dumped. This is what the dealer or PO must have done.The dealer probably didn't know/care. This is not legal in most places. Otherwise, running with an empty cat can't hurt the derivability (it may even help by reducing the back pressure).
-Larry

Gary Stearns wrote:

I noticed in a post today asking about Stebro exhausts a mention of a catalytic converter that came from the factory "empty". I bought our '88 used in '93. It too had an empty catalyst. I remember thinking that this was strange as I bought the Vanagon from a VW dealer (they shouldn't let go of it with a tampered emissions system right?), but the converter showed no evidence of having been forcefully reamed out. Since then I have seen several other posts referring to empty cat. cons. Do Vanagons mysteriously tempt tampering or did VW actually sell them this way. Why? Was an empty converter just a place to hang an O2 sensor? Was it empty because our Vanagons are seen by the feds as light trucks, not having to meet the same standards as passenger cars? Gary