This code indicates that the computer believes that your catalytic system is running inefficiently, i.E. You convert is getting old and clogged. This code can also be thrown by a faulty oxygen sensor. Because the car is running rough, I would estimate that one of your oxygen sensors are providing a false reading, causing the engine to correct for a fuel mixture that does not need to be corrected. This is likely causing you to run rich or lean, and it is most apparent at idle. My suggestion would be to replace your upstream oxygen sensor (closest to the engine) and clear the codes and see if that solves the problem. If not, replace the downstream one too. Oxygen sensors only last so long. Probably a good idea to replace both anyway.
Tuesday, June 1st, 2010 AT 2:04 PM