Truck's been running a little rough lately, so I decided to install some new plugs & wires today, new oil & filter, & a new O2 sensor. When I reached up to remove the old sensor, the connecting wire was just hanging there. Don't know if it was that way when I bought it, or it recently came loose... But the problem is that I can't find the plug to plug the new sensor back in! I've been on top of the motor and under the truck 3 times each, still don't see it... The only thing close are the wires coming from the tranny and the spark plug wires. Can somebody PLEASE tell me where the other plug comes from (what wire loom/direction/etc.)??? Also, it's a '90 GMC Jimmy w/5.7 TBI if that matters.