O2 sensors??????????

[ssmoke14]

My 04 Marauder just recently hit 90k miles. My check engine light came on. About a day or 2 later, it started idling rough. Advanced told me it was the O2 sensors by the cats the first time. I went to buy the sensors and got them to check it again and this lady told me it doesn't really mean its the O2 sensors and that both probably wouldn't go bad.

[RF Overlord]

Post the actual code(s) so we know what we're dealing with.

...and "this lady" is probably right...O2 sensors don't usually go bad in both banks at the same time. Your symptoms sound like a vacuum leak (unmetered air).

[fastblackmerc]

Post the actual code(s) so we know what we're dealing with.

...and "this lady" is probably right...O2 sensors don't usually go bad in both banks at the same time. Your symptoms sound like a vacuum leak (unmetered air).

Yep... need the actual codes to help you out.

[ssmoke14]

Ill try to get the codes. Stuck at work now. Has anyone else experienced this problem? I'm not sure if she ran the test correctly.

[ctrlraven]

By chance do you have a hand held flash tuner? If so you can pull the codes yourself with it.

They could go bad at different times or the same time, anything is possible. Have you recently done work or had work done to the car?

[ssmoke14]

I just had an oil change about a month ago.

[ssmoke14]

And I don't have a flash tuner.

[ctrlraven]

Yeah once we know the codes we can help you more.

[ssmoke14]

Ok I got somewhat of a code. I had to call and ask if she remembered. Cat efficiency threshold bank 1 and 2. Lol I hope this helps so I can get help.

[ssmoke14]

P0420 I think from researching myself?

[RF Overlord]

The rear O2s only monitor cat efficiency...they have nothing to do with the engine's operation, so they wouldn't be the cause of your rough idle. Something else is causing both conditions. Although they could have both gone bad at the same time, that's too coincidental with your other symptom.

[ssmoke14]

Guess I'll be headed to the dealership.

[ssmoke14]

Any more suggestions?

[ssmoke14]

I do remember the lady saying something about my car or the readings were lean.

[MM2004]

I do remember the lady saying something about my car or the readings were lean.

Go back and have them hook-up a scanner to it again.

Autozone will give printouts of what the results are. (Free)

Accurate codes are essential in diagnosing what the issue(s) is/are.

Hold off on going to a Dealer until you post up with the code(s) and may very well get an answer here and save you a helluva lot of $$.



Mike.