Stillen supercharger getting P4020 cod2
 

I had my car at Sebring this weekend and it ran great but monday on my way to work my check engine light came on showing two P4020 codes "Catalyst System Efficiency Below Threshold (Bank 1)". At the track I was running 93 octane with no ethanol in it and thought that might be causing it so I ran it down to 1/4 tank and filled it back up but I'm still getting the code. Anyone ever seen this happen?

NO sir :/

The only on I ever saw was a MAP sensor code, And I had to have the stock sensor threshold raised. Are you running stock cats?

Yes I am but I'm concerned I cooked them. Do you know if the back sensors can be turned off with UpRev? I'm going to take it to the tuner to see how she is running, it seem to be fine accept the light but the light is annoying. I'm headed to New Orleans today so I'm not sure when I can get it there.

You should be able to turn any of them off, But not sure in FL if you emissions check looks for those. I know here in MA I cant touch anything :/

Florida is a free state still, we don't have emissions checks!

I guess I will have my tuner check that it's still running OK and if so I will have them turned off.

Closes thing I could find for an answer:
1.) The catalyst in the catalytic converter is cracked, clogged, or otherwise damaged. 2.) The secondary O2 sensor is malfunctioning. 3.) There is an exhaust leak. 4.) The computer unit is faulty.

You may have burned up one of the cats and it is now clogged or very restricted or possibly an O2 sensor is bad (though usually O2 sensor is a different code).

Don't you think I would feel a power drop if it was clogged? the car feels perfectly normal but I will get it checked out.

I would think you would , Plus the Rotten egg smell that comes with a clogged cat. An rattling going on? Mine crapped out at 59k started rattling, NA still to :/

No Rattling that I can hear and no rotten egg smell. I've thought it smelled rich a couple time but every time I have been in traffic with other cars and can't smell it when it's alone so I'm guessing it's other cars. My exhaust tips are black but they always are and especially after running Sebring.

have you cleared your codes with uprev? if it throw a code it wont clear by its self, so reset it and also data log to see what the o2 senser is ready...i had this happen with my 350z with i had 175 shot of bos on it..i reset it and never seen it again

I have cleared it with a OBD scanner but it came back. I'm still thinking it could be the gas,I told my tuner I wast it extra on the safe side so I know its rich and then ran gas with no ethanol in it. I don't know much about about ethanol but was told it creates weaker gas. I will clear before I drive 1 1/2 hours on the highway today and see what it does.

you can burn a cat out without it clogging they can just stop working, then they clog over time.

Yep. Sorry to say, but you will probably need to swap them out for either HFC's or TP's.

I filled the gas back up and ran around town for 45 min then drive on the interstate for 1 1/2 hours without the light coming on. Not going to drive it again until Monday night when I get back from New Orleans so I guess I will have to wait and see what happens.