My SES light was coming on and this was the code that came up. I just bought the car about a month ago with 147,xxx miles on it. It's a 94 with the 3.4. I have done a basic tune up on it changing plugs, wires, and putting in a k&n. The car seems to be running pretty well, I can't tell if it may have an exhaust leak or something though, because the muffler is kind of loud. And it also idles pretty rough before it reaches operating temperature. Is this something I need to really concern myself with?