Emissions failures are rarely just something "out of tune" unless something
has already been tampered with. Something is going wrong. Intermittent
performance problems are usually fuel delivery or wiring problems. Bad
injectors, spark plugs, ignition wires etc. usually give consistent issues
although weather can have an effect. A defective O2 sensor or circuit can
also cause intermittent drive ability issues. With the failed emissions you
can start there. Consider the failed test as a sign something is wrong. The
more you continue to use it the worse things can get. Non-working O2
sensors, ignition or valve issues, vacuum leaks etc. all eventually lead to
catalytic converter failure.

Yes the injectors are easy to change. You can also do some testing on them.
The Bentley gives some instructions.

Hope this helps,
Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
David M
Sent: Thursday, June 20, 2013 10:36 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Scary happening plus fuel injectors/catalytic converter

My bus has been running fine for years (I admit with minimal maintenance,
except to pass emissions). The other day I pulled up to a light and when it
turned green, I pressed the gas pedal and I barely moved. After crawling for
about 20-30 yards it picked up and ran normally but it felt strange the
first 2 or 3 times I had to slow down. I made it to my destination and then
came back home without further incident.
Any ideas what might cause this? I did have my gas pedal cable replaced a
while back but I don't think it was that. My van did recently fail emissions
which I have not had time to get looked at yet - so it is probably out of
tune. But I'm wondering if this could be a warning of something more
serious.

On another note, how easy is it to replace the fuel injectors? Can I do it
myself? And how easy is it to replace a catalytic converter and oxygen
sensor, can I do that myself? The last time I took my van in for emissions
work, it cost me over $1000 so I hope to avoid that again.

-David (1987 Wolfsburg)