Past two weeks car was progressively running worse and worse. Check engine finally appeared with a P0420 Catalyst system code.

Took the cat off and it was all smashed inside so i gutted it and reinstalled.

Car ran great for half an hour and now it feels like when passing 2500 rpms it hits a wall. However in neutral I can rev no problem but it appears to climb a bit slow.

Any ideas? Is it my 02s? Clogged muffler?

50000 mile 2006 IX with stock exhaust

Thanks,

- Phil

 

Does it rev past 2500 or it literally just feels like crap after 2500 rpm? Cause if it doesnt rev past there, you have valet mode on lol.

 

If it was all smashed check the rest of your exhaust for pieces of the cat/blockage. It's possible you could have hurt the motor if the cat was bad and you drove it.

 

I worried about the motor aswell but I have it resolved for now.

Seems a lic pipe had came loose after gutting the cat, could my boost have peaked higher as a result of the better airflow?

Cleaned out and runs now well but seems very rich, decent black smoke of full throttle 1-2 pull.

What do I risk running like this and what could have been impacted by the previous back pressure?

Sorry for so many questions lol.

 

I have been running without a cat for about a year now and have no problems(except a check engine light due to the second o2 sensor). The only back pressure you need is your turbo, lol.

 

Do you have a wideband? Does it feel like a misfire when your around 2500rpm or trying to boost? In my case, it would misfire and afr will be super lean. Found out my fuel filter was clogged, replaced ut with a new one and problem was solved.

 

Phil,

Have you checked to see if your o2 sensors are fouled or shorted out?

 

Have you checked for boost leaks?

 

Check for boost leaks and get a wideband. This happened to me when my mad wasn't plugged back up when I took it off.