Yesterday i took my car to a shop, and got the main rear cat cleaned out. When the tech took it out, i checked it out, and man, it was CLOGGED ! my car has 193k on it, and my mileage had dropped to like 315 miles a tank, and performance was really slow and you could tell engine was having some breathing issues.

I had the pre cats cleaned out earlier last year, as those things were shot as well. Performance got better after that too, but now it was getting sluggish again.

So far i can see that acceleration has increased alot, i am picking up speed way faster, and it feels much more powerful. Overall, it feels nice, and feels like car has been restored.

Have any of you guys done this ?

 

Just how did the shop go about "cleaning" tha cat?

 

+1

 

popped it off, took a steel rod to it, banged it, got all the stuff out, hollow, and put it back in

 

The MAIN cat? I call bullsh1t. Any reputable shop would have told you to go to hell, as hollowing out the main cat is against Federal law.

 

^^this

 

It depends on where you live honestly, in my county we have strict emission
shops wont mess with used cats but if I dive 20 minutes to the next county they will take out every cat and if you asked them and paid them, make your car more harmful to the environment lol!

 

You're funny.

 

I'd look into your engine for some serious problems if all your cats are clogged like that... Misfire, oil burning etc...

 

Look where the OP is located...it isn't exactly an emissions controlled state like those on the West Coast or Northeast.

Well...some people live in areas where it can't be done unless you find a tech who is willing to do it illegally, under the table payment, and I would imagine for a steep price.



Sounds like burning a lot of oil to me...the clogged cats are only an after affect of a bigger problem.

 

lol who said i went to a dealership or a regular shop....went to a "special" one. It was done in front of me.

Engine is not misfiring or anything, it was leaking oil from the gaskets, which i changed, and the oil cooler assembly, also fixed

 

Right on man, I kind of figured that. When I got my cattman y-pipe, I asked a local exhaust shop what they would want for installation and said he wouldn't even do that because it wasn't oem size. Haha!

 

If people haven't figured out by now - this is normal b/c the cats are defective.

Mine failed, clogged and ruined the engine at 75k miles. It burned no oil until they trashed the engine. The cats should be removed from every car. A recall would be nice, but who has 100 grand sitting around to sue nissan.

 

now, i just wish it shot out flames

 

unplug your camshaft sensor and drive around...lol when mine was going bad and I went to get a new one I shot a flame. But seriously don't its hell on your car.

 

This probably only applies to 5.5 Gen's, eh? I would like to gut my precats, but a good friend of mine who owns a shop and races cars for a living told me it was a very bad idea. Will the precats ruin a VQ30 like they will a VQ35?

 

There are lemon lawyers sitting around waiting for people like you.. You don't need $ up front if you have a strong case against them.. In my state of Michigan if this happened and you sued and won, you'd get a new car off a lot indefinitely..
Read your lemon laws and contact an attorney.. Free legal advice..

 

newbish question, but if you had an original oem cat on a car 11 years old 160k miles... would it be... a preventative maintenance kind of thing to replace the cats? they are not cheap by any means actually quite opposite. but if it is effecting fuel econonmy and performance in the condition it is in from it's agee... it might be granted?

 

They are? From what I've read on hear the pre-cat issues are related to oil burning.

The 3.5 VQ seems to have more pre-cat problems like them breaking apart which I thought was related to oil burning. Not sure if they are inter-related.

The 3.0 VQ has a tendency to throw pre-cat codes, but they don't clog or break apart like the 3.5 VQ. Over time they will clog...eventually.

Technically...they are a lifetime part, but realistically, depending on your mileage you will need to replace them. I replaced my front pre-cat over 100,000 miles ago and it is still ok. I haven only had a rear pre-cat installed for 30,000 miles (had an aftermarket y-pipe for a long time).

Right now my 3.0 Max has over 240,000 miles on it.

 

I still think I'm going to gut my cats...

 

My engine died exactly same time cats clogged coincidence maybe?
Car makes loud hiss and popped flex pipe to find a way out lol.
Then next day compression test verifies 100 in cyl#4...
Swapping motor but def not using those damn pre-cats on my new motor...

 

Thats funny, I think cylinder 4 was bad on my engine too. The piston ring went out. I would recommend gutting the percat's, I had pieces falling off my front pre-cat when I took them off and when I took the engine apart, I noticed that all the intake ports going to the front header were oily and black compared to the other side. That tells me something.

 

wow....i allways heard about the cats doing these things but its definately scary.. and hopefully more rare than common.

dumb lazy question just making sure...

is it correct to say gutting the precats will fail your emissions ?

 

I doubt you will fail emissions unless you are in Cali, if you gutt the main cat then you would fail.