Carbon fouled O2 Sensor:'92 VX - Perplexed

[92VX]

I'm confused on how long you've owned the car, has it ever run right with no CEL codes? Can you take pics of the O2 sensor, including the wiring to it?

[Darkelf]

Originally Posted by Rancho VX

I'm confused on how long you've owned the car, has it ever run right with no CEL codes? Can you take pics of the O2 sensor, including the wiring to it?

I've owned it since mid Jan 08. Never threw a CEL till the O2 sensor got sufficiently fouled a few weeks ago. It did manage to get 43 mpg on the 300 mile drive home after purchase but 'stumbled' at cruising speed, so I guess it never ran quite right. That's why I tore down the intake system (see thread:air intake system rebuild) to clean things out and eliminate variables. Ran great after that for a few in-town trips (don't drive much) till the stumbling returned much worse than before.

Hope that clears things up a bit.

One thing I have done is try and clean the sensor and bench test it so not sure pix will illuminate anything. Standard NTK brand 5-wire sensor. I *think* I may have salvaged it based on the output voltage results (compared to numbers from a known good sensor)

I did buy a 'new' O2 sensor off eBay but the bench test showed an internal fault. Still trying to get refund. If you want to see the test, here is a youtube link:
http://www.youtube.com/watch?v=iXPdhai_5iE

NOTE: This test is with a known good sensor from my other VX ('95) which runs like a top. (just got this one in March but have to fix rust on it)