Nissan mechanic told me that this is a well known issue on Altima's and Maxima's 3/5L engines... I've seen removed converters. They were heavily blocked with carbon deposits. Front cat was really blocked (up to 70%) of cross section. Surprisingly the lower cat was also blocked.

This problem is really annoying during driving.... At the beginning I thought that this is a transmission. Acceleration was very power and engine valves hummered when back up pressure increased at 2500-3000 rpm. Once car almost stopped when I drove uphill because of lack of power. I barely maintained speed on a high way.

Now car is just flying on new cats. I wonder for how long....

I purchased Nissan Altima 2002 SL from a dealer recently and it was fine when I purchased it and after 3 days of my purchase it's started showing up some bad noise form catalytic converter and with misfire in the cylinder 3 from and it also consuming a lot of oil into the engine. I showed this vehicle to a mechanic he said that the only solution is to replace the whole engine and catalytic converter. I am totally lost and I have no idea what to do on this and the dealer is not in a position to take it back as I initialed on 'sold as is'. I checked with Nissan they said that the extended warranty is finished on this vehicle. I am not sure why these companies make some junk to throw it onto the customer's face. Please help me to find a better solution from my case.

I HAVE READ MANY COMPLAINTS HERE ON THIS SITE WICH ARE IDENTICAL TO MINE DUE TO FAULTY CAT CONVERTER...THIS DIFFRENCE IN MY APPROACH TO MOST COMPLAINTS ARE,THAT IM GUNNA STAND IN FRONT OF EACH NISSAN DEALERSHIP WITH A HUGE SIGN SAYING "DO NOT BUY NISSAN MAKER KNOWS AND IS AWARE THAT THERE CARS ARE LEMONS!!" I SUGGEST YOU ALL DO THE SAME NATION WIDE!!!!!!!! ALSO CONTACTING CHANNEL 7 NEWS HERE IN LOS ANGELES TO INVESTIGATE NISSAN WITH THERE WICKED WAYS OF RIPPING CONSUMERS OFF!!! THANKS HANK SERRANO !!!

So, a chunk of what I call the honeycomb in the catalytic converter came off and lodged itself into the exhaust pipe. The back pressure was so bad it blew the head gasket and now I have problems. I used a head gasket sealer(glue) to try to fix that problem and so far we are on our way to a possible fix, but the jury is still out as it is still giving me a little cough starting up, but I just did this 2 days ago. We will see what happens.

It has been burning oil like wildfire for about 6 months or so and I believe I will have to replace the engine or do a complete overhaul if I want this car to continue getting me around. I'm pretty handy when it comes to vehicles and I have a lot of mechanic friends, so we should be able to knock it out, but I know if we go to fix the head gasket and do the rings, it is going to be a pain. Thinking about finding another engine at a junk yard, but how long until I have these problems again?

I will say one thing about this car. I really didn't have problem once until 100000 miles, so I feel like it has been a pretty awesome ride!!! Didn't have to pump any money into it except routine maintenance. So now that it has been payed off for almost 5 years, I think I can say that the upcoming work will not kill me, but in this economy, who knows.

i am a mechanic so i replaced the sensor and converter myself. this same 2002 Altima 2.5l heater doesn't work at idle. throws cold air, but when your going down the road works fine. took it to dealer, charged me $75 dollars and they didn't fix problem.also check engine light always on. code p1456.. evap. canister problem. i'm replacing evap. canister vent control valve ( march,2011) will see if it passes emission test. due in may,2011. this car is so low to the ground. i've replaced the exhaust mount twice.

i got this car new. may 2002. it now has 155,000 . my 1st and last foreign car.

never had trouble with my gm cars/trucks.

A steady deterioration of acceleration ability on my 6 cylinder, 3.5 liter model makes it unsafe to drive on the highway. The 6 cylinder models have 2 rear exhaust pipes, and endure double the catalytic converter stress and expense as the 2.5 liter models. Diagnosis by a reliable local repair shop shows both catalytic converters are congested and need to be replaced at a cost of about $2300. But while NHTSA federal oversight has gotten Nissan to issue a recall, #27629 in March of 2003 (NHTSA Campaign ID number: 03V084000), Nissan only acknowledges vehicles with 2.5 liter engines as qualifying for the recall. Regrettably,the recall wording makes it ambiguous to prove whether the catalytic converter exhaust problems also extend to Nissan's 3.5 liter vehicles. I am filing a complaint that tries to get NHTSA and Nissan to explain whether or not the frequent catalytic converter breakdowns listed on this page for 3.5 liter vehicles are also related to the same Nissan design deficiencies. When so many vehicles shown here experience the same problems, it is incumbent for both manufacturers and regulators to acknowledge that both models are affected by the same flaws and to provide the remedies and relief. For me, it's a doubly expensive proposition, and yet the lack of explicit wording of the federal recall is possibly allowing Nissan to get out of covering these vehicles. I am doing what I can to hold their feet to the fire and at least find a decent explanation why the 3.5 liter engines may or may not also fall under this fatal Nissan design flaw. I welcome any input from other 3.5 liter owners who would feel free to contact NHTSA's Vehicle Safety Hotline at 1-888-327-4236 and file additional complaints about Nissan Altima's catalytic converter problem.

I bought my nissan new. Kept garaged,and always maintained. Check engine light comes on. Cat problems. Changed O2 sensors. Still having problems. Mechanic worked on car, couldn't figure out why plugs were not coming out. Researched, found out it had been recalled. I had all paper work and found it was recalled in 03 for the problem. No problem since now when cat went out. Nissan no help, said not on recall now. too bad.

I am so pissed. I will join any class action lawsuit against them. They should stand behind what they sell Not have a car that turns to junk after 77,000 miles.

I had my cat converter fixed in September and after that was fixed my car started using excessive oil. I have been pouring it in quarts at the time. My car is not smoking and I have been taking it back and forth trying to find out what the problem is. Yesterday as I was traveling it ran hot and now it will crank at all. I don't have a clue as to why that happen unless there is a problem with the radiator. When I first got my altima I was having problems with my lights blowing out as most of you know there was a recall for that.

I have been properly servicing my car every since I bought it trying to make sure I took good care of it. At this point I had to shout out to someone because this is getting stressful. I feel that something need to be done about this because if there was not a defect then everyone wouldn't be having the same problem. Excessive oil usage, cat converter or heads blow seem to be to the extreme with the 2002 Altima. We need results and quickly.

Just to give you a heads up. I took Nissan to court for the same problem you are having. Told me that since I could NOT produce ALL oil change receipts since 2002, the engine failure would not be covered, even though I had been through 3 CAT converters.

I happened to speak with my Nissan tech who worked on my vehicle. He advised that Nissan is aware of the problem, however they will not address it because it will cost them too much.

Also, to let you know, do NOT use the Lemon Law Attorneys being mentioned. They wasted my time, settled my case without my authorization and got me a measly 1,000 which I had to split with them for being nothing but rude and dishonest. I attempted to go after Nissan on my own in court. The Nissan attorney threatened me with letters and verbally that if I did not accept the 1,000 they were going to sue me. They attempted to force me to sign a gag order, an indemnification clause and agree that I would not speak to the press about this problem. Still have the letters! You are better off suing on your own and get an ASE certified tech as a key witness. Hope this helps, good luck!

Greetings, I am the unfortunate owner of a 2002 Nissan Altima 2.5L which I purchased brand new in 2002. The vehicle has been maintenanced as required and has very low miles. I have only now reached 75K after almost 9 years of driving it. Three months ago I started having the issues, poor gas mileage, and engine shutting off while driving down the road, excessive water consumption, and excessive oil consumption. I kept an eye daily on all my fluids and have reached the point where I can no longer drive the vehicle. It began pouring blue smoke out of vehicle and it is currently in shop. The oil indicator light does NOT work at all even when the vehicle has no oil at all in it. Temp gauge is not working at all. All issues related to a failed catalytic converter. MASSIVE oil consumption, took a trip to the beach last week less at around 130 miles. Checked oil before leaving right on target. Woke up checked oil Friday night upon my return and burnt almost 4 quarts. The oil light is not working at ALL again. NO indication of any issues on gauges. I am highly upset as everyone else is to say the least as I purchase the vehicle based on Nissan's reputation and reliability. This was the first car I ever purchased on my own brand new. I am in the process of getting the convertor replaced this week. It's obvious that the problem is known by Nissan and they refuse to accept any responsibility, based on all the research which it's obvious. I would be happy to join in any filing or attempt to file a suit against Nissan. They need to step up to the plate and be held responsible for these issues. The horror stories I have read are identical to the same issues and problems I am having at 75K. kkhall01@yahoo.com.. If you have any positive experience with Nissan stepping up to the plate please contact me and let me know. Thanks!

Having the same problem with my altima I bought it in November 2007 with 129,000 miles on it and had to replace the engine in it in March 2008 because it was burning to much oil. The same problem has occured again and my check engine light is also on so I took it to the dealership and guest what the pre cat system has fail causing damage to my engine and nissan north america do not want to do anything to fix what their fault pre cat system has caused so I am willing to go ahead with a lawsuit if anyone want to file a class action lawsuit i am with it.

I have problems adjusting my seltbelts. How do I fix that problem? Also, I just bought a 2002 nissan Altima and I am having major problems out of it. My husband and I let the Nissan dealership look at it and they said the motor went out because of the catalytic converter was suck into the engine. Those problems accured in three days after I had it. The dealer rebuilt the engine, but when I got it back it was still burning and losing oil. Oil was on the ground each morning we had the car. We took the car to a nissan dealership; they ran test on the car to what problem they could fine. the only thing they came up with was a oil leak. My husband and I let them fix the oil leak and four days after the car would not start. Nissan told me I needed a new engine, but when I let another mechanic look at it they said the timing was wrong.

My other question is there any 2002 nissan altima good? Also, Do mechanics at the nissan dealership only fix a little of the problem to keep us coming back? What year nissan Altima do you think is better to buy that you think that will satisfy you all customers? It's 2010; Do you think 2002 Nissan Altima will ever get right because eight years had past by and same problems? Be honest please

So I just bought new tires and was all ready to head on a 2-hour trip north for some snow time when my "check engine light" comes on. Totally afraid, I had it brought to the Nissan dealership. After 3 hours, I got a call stating that I need a 1) new cat converter, 2) fix engine mount, 3) radiator replacement (for leak), 4) transmission fluid change, all totaling about $2000. Knowing that the dealership is kinda shady if you don't have any type of warranty, I brought it to an independent Nissan repair shop. They found out 1) yes, I did need a new cat, 2) my O2 sensor was totally fried/warped and needed to be replaced--they said they only found it out because the area was already open, 3) I was super-low on transmission fluid, 4) that they did not find any leak in the radiator after a hot and cold pressure test. Got it all replaced for $1500. I can't event imagine how much it would cost for the O2 sensor to be replaced if at the dealer. That was just the start of my worries...now I'm burning oil, approx 2-3 quarts weekly! But that's a whole other gripe fest. I had a Honda for with over 150000 and the only reason it broke down was because I got tired of driving stick...ah, the good ole days of a reliable car...prob gonna buy Honda or Volvo this time...

I have only the one car, i bought this car new in 2002. this car have had more problems than any car i have ever owned. i've had over $13,000 dollars worth of work done in 2 weeks, my car still ain't fixed... now they say i need a motor because my cad. converter came apart and damaged my motor, they want take responsibility for it. im not workin at this time because of health problems and can't afford to pay anymore money out for this car....they've had several recalls for this same problem but said my ven# wasn't in it. Nissan ought to be ashamed.

I bought used from a Nissan dealer in Agust of 2008. Car had been fine until about two months ago then started using excessive oil. I mentioned to my Oil change place and they referred me to a NTB recall on the precat causing possible engine damage.

I took the car to my nearest dealer, they told me "there are no outstanding issues on your car". Well, today, June 23, 2010 the car has died...my friend, a mechanic, said it appears valves/rings due to high pressure at the oil cap and the white smoke and smell from exhaust pipe!