Symmetry

Check engine light is reporting my cat efficiency is low. I vaguely remember my cat being stuck to the exhaust manifold when I had it replaced under warranty. If I go aftermarket, is it part bolt-on or does the whole thing have to be cut out and a new one welded on?

And do the O2 sensors need to be replaced?

Thanks.

JDMFellon

Really depends man, have you taken it to a shop? Most shops know ways around those blasted engine check lights, but If I were you I'd pick up a highflow cat and get a shop to replace the stock one, no you don't have to replace the stock O2 sensors and yes they will have to weld the new cat in place.

Symmetry

Good idea. My cat should be OK considered it was replaced recently and I have an aftermarket exhaust, so I'll look into a workaround.

kingjames1983

after market cats are usually generic... so most likely you will have to get it fitted and welded to size. If your previous cat is clogged there is a good chance your o2 sensor is gone. What I would do is replace the cat as long as you know that is the problem then reset the CPU by pulling the battery terminal off for a minute or 2 and then reconnect. If you throw an 02 sensor code then change that and hopefully your problem is gone... I'd try to borrow one off a friend so you dont waste the money to find out its still throwing a code. If that fixes the code then go buy one and give the borrowed 02 sensor back

Robb

iTrader: (1)

Also, if you have a bad thermostat, it will cause a rich mixture, causing bad emissions.
Replace the PCV valve while you're at it. Cheap and easy .

chris_v2

What about OEM carpet?

chris_v2

and a p0420 code could be as simple as a vacuum leak. You need to get the car in for a proper emissions diagnosis. They will test cat efficiency, o2 sensors, fuel trim values, etc.