My truck failed the emission test. I've done several things to it already like replaced plugs, wires, distributor cap, rotor, put a can of Seafoam in the gas tank, filled it up with high octane gas. I just ordered an oxygen sensor that goes before the catalytic converter. This is a 3 wire sensor that comes with a plug attached. The plug on the old one is visible from underneath the truck, but I can't reach it to see if it will pull down so I can disconnect the plug. It's located between the firewall and engine. Any ideas how I can pull it down to get access to it?