Thread: p0420

I had a p0420 a few months back. I had the car for about 10k miles before it started to happen. I dont notice any loss in performance, maybe some in fuel economy. The cat on there was a universal magnaflow welded on, it seemed to have been falilng apart causing substrate to go in the o2 sensor. I replaced the cat with a magnaflow direct fit and the code is still there. could it be the o2 sensor is actually bad or what?

Thanks

Did u clear the code after fixing it?

one of them emulators may fix it for ya. it moves the o2 sensor out of the exhaust stream.

I didn't think those worked on 04+cars

it may being hes a v8. after market cats can be a problem as always, they flow to good.

I've got another thread open on it and they suggested using defoulers to move the o2 out of the flow

Originally Posted by sirricealot

I've got another thread open on it and they suggested using defoulers to move the o2 out of the flow

Be prepared for this thread to be closed.

Why would you even start 2 threads on the exact same subject?