it seems that my cat is pluged up ,on my 95 legacy L a/t awd wagon 2.2 . what would happen if i degut the cat ? yes i know it is not legal

I did that years ago on an Oldsmobile, but that was before cities started doing smog e-check testing in order to get tags (license plate) for your car. Don't know if they do that where you live.

 

If you did that on your Subie, you would relieve the back pressure on your exhaust, but that would probably trigger the check engine light on your dashboard, as I think the 02 sensor would detect too much dirty exhaust in the muffler system.

 

I would not recommend running your car with a bad cat. Go to a low cost muffler shop to have a universal type cat installed on your car. It wouldn't cost much, if replacement cost is an issue.

I know it's not a Subaru but in the 87 Mazda 323 (fuel injected) I had, the cat was completely burnt out.. no issues or CEL. It even passed Denver emissions tests, so it might not affect anything at all.

 

I would be surprised if the loss of backpressure would allow enough extra exhaust gas to flow through to affect the O2 sensor reading but I am not a mechanic..

 

I don't think it hurts anything else (other than the air quality) if the light doesn't come on

Get a vacume gauge, that will tell you if the cat is clogged up. If your not in an emissions state you can degut the cat with no engine performance issues. You may get a CEL as the downstream o2 sensor is going to see dirtier exhaust then it expects.

 

 

nipper

ok, my mpg is now 12 city, and getting worse, no E check here, and real slugish , but going to change the plugs and wires, already changed the air filter ,fuel filter , thanks

OK give us more details. Dont just go throwing parts at it.

 

How many miles?

When was the last time the car had a timing belt change.

Get a vacume gauge , it will tell us many things about the flow of gasses, and the state of the engine.

When was the last time an O2 sensor was replaced?

 

nipper

new timing belt, water pump, 162,000 on motor, just did a tranny flush / fill, the reason why i say it is bad cat ,is because of the bad egg smell when i start it up and idle,

new timing belt, water pump, 162,000 on motor, just did a tranny flush / fill, the reason why i say it is bad cat ,is because of the bad egg smell when i start it up and idle,

 

Bad egg smell doesnt mean anything. Go to the aurtoparts store, get a 19.00 vaccum gauge (your ready to spend another 60 on plugs and wires, why not 19.00 on a gauge). Lets make sure timing is on the nose, the valves are seating, and the cat isnt clogged.

 

Blu gets a rotten egg smell every morning, and just passed NYS emissions.

 

If the car is free revving, has plenty of pickup, its not the cat.

 

nipper

ok, i;ll buy a vacuum gauge when i have a chance , limited parts stores in my area, and they close early, i have no clue when the plugs / wires were changed , when i got the car the mpg was aleast 25mpg just 2 months ago , since then it has dropped badly, so why another 60 bucks , when i never replaced them