Need help and advice:
scenario: My husband and I were taking a little joy ride in our Crossfire (2005 limited 150K miles) everything was fine until my husband punched it and the car sputtered and spit, it was ugly. We limped back home. We have noticed that at 3rd and 4th gear around 2500 rpm it seems to skip just a little then corrects itself. We just bought the crossfire 1 month ago and have driven it three times. We have the codes and it's sad, P0303,304,305,306, P0300. The mechanic mentioned it might be the catalytic converter, but I wanted to ask the real experts. Check engine light def on.

 

It sounds like it could be a plugged Upper Cat. They age, they crumble, they plug the down exhaust pipe
Does the car just choke and sputter when you try to accelerate?
Happened to me, passenger side. Removed the cats. Problem solved.

 

To test for a clogged catalytic convert preform a back pressure test: Unscrew an upstream O2 sensor, screw in a pressure gauge, start car. Gauge should read under one pound pressure, greater pressure indicates a clogged exhaust. Doesn't take much time and is a lot less than replacing a converter.

 

Hey, UrbanE, how do you pass smog without cats?

 

Don’t have to worry about that here. No tests where we live.

lots of fresh air