Bad Cat?

[BiXLL]

Over the past month I have noticed a drastic drop in my gas mileage. I have been getting 28 to 30 mpg for a long time. All of a sudden over the last 4 tank fulls I am getting more in the 25 mpg range. I have replaced plugs cap and rotor and it did not help at all. I seem to be noticing much more the rotten egg smell of cat converters lately, and after car has been run about 10 miles it feels like the motor is almost slightly fighting itself at a steady cruise speed of 45 to 55 mph, almost like a slight miss. I am wondering if maybe my cat is clogged, or getting clogged and as it heats up is maybe restricting flow???

What are the signs of a cat going bad, and what can I expect to pay to replace it. I am not interested in some high performance, high dollar type cat, just something that is going to allow me to pass the good old Pa. emissions test.

[94_240sx]

Remov the cat and check inside. It should be grayish looking. Red or brown color is bad. I couldn't pass inspection due to high NOx, so I installed a used OEM cat and I passed it yeterday. I didn't notice performance difference though. After market cats are not good since they are 2 stage cats and they don't fit well. OEM cat is 3 stage.

[Eikon]

Have the gas stations turned over to "winter blend" fuel yet? Colder weather could be an issue.

You have three 'verts.. you could always swap one of the other cats over and see if the car runs better or worse.

[BiXLL]

If anything, they would run better on the winter blend. So far as taking one off the other verts, I like being alive, and unharmed. Do you have any idea what the wife or son would do to me if I took their car apart for no reason????

I will be changing the exhaust as soon as I find one that is not of the "high performance" fart can type that makes the car louder, as mine is rotting off just behind the first muffler. I will be able to do a good visual on the cat then.

[onosqv]

I seem to be noticing much more the rotten egg smell of cat converters lately

That's one of the first signs it's going bad. Replace it.

[94_240sx]

That's one of the first signs it's going bad. Replace it.

Thinking back, I had that smell for a while and somehow it went away. One of the mesh thing inside of cat was warped on mine too.

[Mista Lee]

Since i see that you have 3 verts..would you mind parting the rear speaker/arm panels?been desparately looking for one and i'm willing to pay for shipping and everything.let me know.

[94_240sx]

Since i see that you have 3 verts..would you mind parting the rear speaker/arm panels?been desparately looking for one and i'm willing to pay for shipping and everything.let me know.

All of them are in good working condition. I might be able to help you, but not so soon.

[BiXLL]

All of them are in good working condition. I might be able to help you, but not so soon.

correct! I drive the black one, the wife drives the red one, and my step son drives the white one.