RW> An O2 sensor won't give you much of a warning. It just loses its ability   
   RW> to perform as intended, messing up the MAF/O2 loop reading. i.e. my Z28   
   RW> used to give me fits with O2 sensor codes (check engine soon), but that   
   RW> stopped after changing the 'brand' of fuel used.   
      
   As part of the 75% rebuild of my Monte Carlo, I did replace the O2 sensor -   
   about 2 years ago.  One day, I just received the "Check Engine" light.  I took   
   the code scanner out of my trunk and checked the code.  It had to do with the   
   O2 sensor (front bank) not getting to the proper temperature.   
      
   Apparently, my first bank O2 sensor is heated to make the system go to closed   
   loop faster.  The heater element on the O2 sensor stopped working.  Replaced   
   it and all was well.   
      
   RW> Insulation? No. Sealed connectors, no. Cars with non-sealed distributors,   
   RW> yes. Cars with old frayed wiring (no insulation left on them) no. At   
   RW> least   
   RW> not as long as they weren't hot wires touching ground.   
      
   I'm going to give that a try on the Durango - since there is still areas of   
   "crud" in there from the antifreeze/transmission fluid explosion.   
      
   RW> I put a high performance Granateli MAF in my Z28 back in 2001/02...it's   
   RW> still going and I also kept the original, stored in the Granateli box...   
      
   I do the same thing.  When I replace a working part, I save it in case I need   
   to switch it back out.  I'm amassing a nice collection of stuff.. :)   
      
   - Mark   
      
   --- WWIVToss v.1.50    
    * Origin:  http://www.weather-station.org * Bel Air, MD -USA (1:261/1304.0)