I'm working on a 96 LHS with a 3.5. It just had plugs and wires done by someone else trying to fix an occasional but very obvious miss-fire. Two things I noticed looking at the scan tool data were that the long term fuel trims were both very negative, bank 1 at -25% and bank 2 at -18%. The other thing was that the intake air temp was reading 160 - 180 degrees. I know it can't be that hot so I was going to pop the IAT out and verify that it was bad but I can't find the thing. Most other cars I've worked on have it right there in the intake duct. Has anyone seen this problem before and/or does anyone know where the IAT sensor on this beast is?

Under the plastic cover in the center of the intake plenum. Intake temps in these engines do run pretty hot, try laying your hand on the runners after driving it for a while, I bet the hand won't stay there for very long before you pull it away. I wouldn't be suprised if the temps you are now reading are considered normal.