[Purplewgn2000]

Well boys and girls. I have yet another question/problem. I have fixed my knock sensor and ridded myself of that aggravating problem; now I have a completely new problem. I have another error. I have what looks to be a failing cat. I get a "catylist below acceptable threshold" error. Could this be a sensor failure or the cat itself. Remember I do have 176,000 miles on this car with no proof its ever been replaced.

If the cat is failing I will replace it soon, but is there an aftermarket upgraded cat I can switch to. Maybe something that will flow a little better than stock. I always feel the need to ask, freeing up exhaust flow is always a good thing. When I get my Corsa exhaust it would help to relieve some of that exhaust backpressure.

 

[elwesso]

I bet a sensor has gone bad...... If you havent let the car misfire or run really rich, the cat is probably still fine......

Usually the O2 sensor will throw a code if its running too rich..... Which could mean a misfiring cylinder.... Do an OBD diagnosis, and tell us what codes come up......

There are high flow cats available.... From where/brand/price, I cant tell you..... They do exist......

 

[Purplewgn2000]

I bet a sensor has gone bad...... If you havent let the car misfire or run really rich, the cat is probably still fine......

Usually the O2 sensor will throw a code if its running too rich..... Which could mean a misfiring cylinder.... Do an OBD diagnosis, and tell us what codes come up......

There are high flow cats available.... From where/brand/price, I cant tell you..... They do exist......

Well, it throws up a code P0420. Which in the book is a non-factory specific code meaning "Catalyst System Efficiency Below Threshold Bank (1)". I have thought about a sensor being bad, but I have proof that it had been replaced at 80,000 miles. It is possible that 100,000 miles later the sensor could be bad again, but what do you think?

 

[elwesso]

Sensors can last anywhere from forever to only 50k..... Depending on the sensor......

Do you have a FSM?? I bet you can find a good diagnostic chart about it.......

 

[davesdeville]

Seems possible to me... after all it was replaced at 80k and then another ~100k was put on it. It's a good chance it's the sensor, and its cheaper to replace a sensor than a cat..

 

[Purplewgn2000]

Seems possible to me... after all it was replaced at 80k and then another ~100k was put on it. It's a good chance it's the sensor, and its cheaper to replace a sensor than a cat..

Good ideas, I think I will replace the sensor first. I have a buddy working at the parts house. If the sensor doesnt work, I will just take it back and buy the cat. Thanks again.