NOx is caused by excessively high combustion temperatures. Usual causes
are a lean fuel mixture or over advanced ignition timing. Since the
Vanagon does not use EGR, the engine settings are extremely critical.
The Cat has the major job of reducing the NOx and all aftermarket cats
do not have as much active material as the original so they do not last
that long.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
Of Mike Miller
Sent: Friday, September 09, 2005 12:09 AM
To: vanagon@GERRY.VANAGON.COM
Subject: NOx high

Vanners,

My van passed smog but the NOx was just below the maximum. New cat two
years
ago.

Any likely causes to look at?

TIA

Mike