[JL8Jeff]

Check things like the AIR check valves to make sure they are working properly. I've seen a few of the AIR check valves stop working and it allows air into the exhaust that the computer isn't expecting and will throw off the O2 readings and make the computer make bad adjustments. Also, did the car really have 2 different types of plugs in it? The AC's look like platinum or irridium, but the NGK's look like regular plugs. Also check the EVAP lines and valves to make sure it's not sucking additional air constantly from the tank. It almost sounds like you have a vacuum/air leak on the driver's side throwing off the O2 readings and the cat is running hotter as well.