I have a 97 Rodeo 3.2L V6. My check engine light has been on and off for the last week with error code 440 (Evaperative Emmission Control System Malfunction). I looked at the O2 sensor and I have a small oil leak above the sensor. The O2 sensor is soaked in oil on the outside. Anone got any Ideas if this is the problem? (I didn't think the oil would affect the sensor on the inside of the pipe.

P0440 isn't associated with any of the O2 sensors.

http://isuzufaq.ibctech.ca/#faq2a

tighten your gas cap.

The gas cap is all the way on, but it is one of thoes aftermarket locking caps. I will try to find where I put the factory one

The gas cap is all the way on.......

Doesn't matter. If the check valve in the cap does not seat & the pressure bleeds of the gas tank over time, you will get EVAP system codes. You can 'usually' tell if you can smell a gasoline odor around the fuel filler area.
G/luck
Joel