I got a check engine lite last week. the code refers to cat conv. efficency. I did a search online for info about cats and it seems the exhaust gas should rise at least 100F as it passes thru the cat. I used an infrared thermometer and measured the inlet/outlet of my cat. it is 380F in and 280F out. that does not seem right. I talked to a muffler/tuneup shop and he said cat temps have nothing to do with how the cat is functioning. or put another way, he said i was over analyzing the situation. my friends car measured 380F in and 500F out. but the mechanic said that was a different brand car and all cars run different. I still think I need a cat. but i also think the temps are valid and an indication of a cat problem.