The sensors rarely go bad. What does go bad is the connection to it.
Replacing the sensor seems to fix the problem but the only real change is
the wiping action making a better connection. Yu could have accomplished
the same thing by disconnecting and reconnecting the old one. The other
problem is a bad connection at the chassis. Of the two wires to the
sensor, one is from the ECU and the sensor controls, (sinks) the current
to ground with the resultant voltage drop telling the ECU what to do. The
problem is made worse as the idle stabilizer uses the same sensor so a bad
connection messes up both. Clean and inspect all those chassis connections
near the ignition coil. The sensor connector is the same as an injector
connector. Aftermarket pigtails are available or you can get the good
stuff from the dealer.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Jeff Lincoln
Sent: Tuesday, July 10, 2007 9:54 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Temp 2 Sensor Questions

Well, back in late April or Early May I replaced the Temp 2 Sensor and it
cured what ailed my 90' with the rough rich running and back firing. It
was
great. Well, a couple weeks later it started doing the same thing again.
Common sense says it was the Temp 2 sensor agin - but I have no common
sense
and thought it couldn't be because it was just replaced. Well, I just put
in
a new sensor and sure enough that seems to have been the problem again.
Someone suggested that sometimes the sensors can be bad off the shelf.
That
may be the case - however I was also wondering if there is something else
that could have made the new sensor go bad so quickly?

What does everyoneout there think? Can something make the sensor go bad
within a short period of time or did I just get unlucky and get a poor
sensor to begin with?

--
Thanks,

Jeff
90' Carat (It's Blue, It's Beautiful. Now sporting a very unstylish brown
interior taken from the parts bus)
86' (We call this one Parts)
85' GL (Sidelined and feeling neglected)