The car has had poor mileage for a year or more, but the code only came up for o2 sensor. The bank two catalytic converter is a real pain to replace as you have to take off the upper intake manifold just like tuning it up. I think that it was intentionally designed by Nissan so you have to spent money. Two screws are in the back by the fire wall and the other two are under the car. The only thing is you have to remove the Y-pipe, the o2 sensor then can you start to remove the final two of the four screws. This no one man job unless you have mad mechanic skills and the tools to match.. I now see that I made a major mistake in thinking that Nissan would continue the quality as if they were still made in Japan. I WILL NEVER BUY A ANOTHER NISSAN/INFINITY PRODUCT AGAIN!

I have a 2005 Nissan Altima with a little over 142,000 miles. A week ago after filling it up, the check engine light came on. We drove it acouple of more days thinking maybe it had to do with filling the tank. I then took it to my favorite shop, since the car is out of warranty. They told me that Nissan has several tech bulletins out on this and that they could not fix because it required a special code that the dealers have to reset. Also told me that it might need to have the cat converter fixed. Took it to the dealer where i purchased this in 2005 brand new. They called me back and told me I needed a new converter and that it was going to cost $1100.

I asked why they had service bulletins out and also how many of these they fix a year. They said the bulletins were just normal tips and that they only change out 1-2 a year. In my line of work this tells me they have a design flaw. When I asked why mine was their 1 or 2, they laughed and said because.

I called the regional Nissan and complained. They called me back 26 hours later to tell me that they will not stand behind their product because it had been too long. I have owned cars from all major automakers, Toyota, Honda, Ford, GM and Chrysler and I have driven them all well over 150,000 miles and never had to change a cat converter. I nicely told the region rep from Nissan that they had lost a current and future customer. And I am on here to let you know that Nissan does not stand behind their product and not to buy. Neither I nor my family will step foot in one of their dealers ever again.