mcwarren2

I have a 2001 pathfinder, 56000mi, that I have been experiencing issues with the check engine light turning on and off intermittently. I also have a rattle that sounds like metal on metal during accelerations, but all of my checking of heat shrouds, none are loose. I took the car to my local part shop and they scanned the codes. The first time codes tripped saying both Catalytic converters were blocked. Since the catalytic converters are under warranty I was going to take it to the dealership. The light went off after about two weeks and I had not made it to the dealership. For a couple of weeks the light would be off one day and on the next. About a month after having light turn on I want back and had the codes scanned again, I was given a code for one of the rear O2 sensors(can't remember which one because my wife took it in). I am confused because of receiving two separate codes. I am leaning towards a problem with the computer or an exhaust leak.

1) Is this likely to be the same programming issues for the O2 sensors that I have been reading about from previous posts?

or

2) Could the rattling that I am hearing be a leaking exhaust and would a leaking exhaust cause strange codes to be tripped on the computer?

Any other help or suggestions would be greatly appreciated.

Thank you,

Mark

steveavant

I am having the same kind of problem, if you are saying that you have a rattling sound and no heat shield are loose it might be the catalytic itself that came apart inside (it is made of a stone) thats giving you that sound. Take your truck to the shop (b/c is under warranty), get the the ecm scanned (even if the check engine light is on) because the code will be stored in the computer, if is a "catalytic efficiency" code you need new catalytics, if it a "lean" code it might be a leak or a fuel delivery problem. but get that check. If they found nothing with that insist on a backpressure test. They have to do all that at no cost. By the way... there's a bulletin for the O2 sensor were they reprogram the parameters of the O2.

Hope that help, and let me know how it goes b/c mine is off warranty