Ok, so I think I'm just going to replace the O2 sensor in both my 82 and 83 240s. It's technically scheduled maintainence for those years and easy enough to access (at the base of the collector). Based on my O2 Sensor education here:

http://www.brickboard.com/RWD/index.htm?id=1203523

I'm wondering about shielding the sensor. I'm just thinking that it would be nice to have a small shield over the top and bottom of the sensor to prevent contaminants getting on it (oil from the top and road gunk from the bottom). I'd like to fabricate a small piece of sheet metal that would fold and form a cover for the top and bottom, being held in place via the sensor. Is there any potential problem with this? I'm thinking of leaving enough room around it to get a socket on it.

Would metal shielding skew the sensors readings? Obviously some things can affect it's calibration/accuracy so I don't want to do anything that would intentionally throw off it's output.

Any one's thoughts are greatly appreciated.

Thanks
a-