So my cat has been rattling (combs are loose, it's not the cover) and my gas mileage has been decreased since of about 2-5 mpg. Could this be from the damaged cat?

For reference i used to get:

City/Highway 25/29

Now

21/26

Thanks

 

Yes...it is increasing back pressure on the exhaust.

I believe emissions controls equipment have a longer warranty than other parts of the car. You may be able to get it replaced under warranty if so and if it applies to the cat.

 

8 Years I believe.

 

I have an aftermarket header and intake and no stock replacements...declined. I have a berks highflow cat on the way anyways : P. Just wanted to doublecheck it's the cat.

I'm going for a dyno session this saturday and prob won't have the high flow in time. It should get me in the ball park if something is seriously wrong with my car. 60k mile MY04 should get around 200whp if healthy right? What would the difference be in 90 degree weather?

 

You might post in your local s2ki forum. There are probably a few folks with test pipes who would have their cat collecting dust in the garage (I actually have 2...one from a buddy's car). And someone may let you use a cat till your replacement arrives and to get some good numbers at the dyno day. A bad cat can cost you 15whp.

 

NO WAY 15HP!! well then since this topic is up. Anybody with a stock cat lying around within 100miles of Jacksonville, NC??

 

Can a fuel treatment cause your cat to clog? Is there an easy way to tell if its clogged?

 

It's rattling like crazy at idle, and it's not the heatshield. Plus i'm getting a big decrease in gas mileage after the rattling started. I don't use fuel treatment.

 

I am asking because I have had a serious decrease in mpg recently in my Pilot. It has 120,000 mi and recently had a fuel treatment done and a brake job. I'm wondering if one of those caused the problem as I haven't gotten any codes and can't figure out what the problem is.

 

fuel treatment or engine treatment like seafoam? Check sparkplugs. Are you burning oil? No codes from 02 sensors you say. hmm, does the pilot have a MAP or MAF sensor?