It's the stupid things that alway get me, so I make a point of checking the stupid things first thinking as stupid as I can. The plug is secure in the socket and I blew it out with contact cleaner for good measure, but I'm about ready to cut into the wiring harness to see if I can tease out the wire and find something wrong with it. I know driving these salty northeast roads did a number on my fuel tank wires. Maybe some crack in the insulation has done the same to the O2 wire.

'89 P'up, 2.6 I-Tec, 488,000 miles and done... gone to the great beyond