[superchi]

Wondering if anyone here might have encountered either of the issues I've run into 9r might have any hints on how to troubleshoot these:

2017 SS manual, was bone stock before having a Stainless Works NPP catback installed at my local dealership. After a few days, CEL came on with code P0420 (Catalyst System Efficiency Below Threshold (Bank 1)). I took it back to the dealership suspecting that there may have been a leak from not seating the exhaust correctly. They ended up making the call to replace the driver side cat, which happened to be covered under warranty.. Unfortunately, the same code has popped back up after a little more driving.

In the time between taking the car back to the shop, I installed a Roto Fab intake with oiled filter. Not too long after, I started getting a CEL with pending code P0121 (Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem. I would go back to the stock intake to try to rule this out had I not accidentally sheared off the one of the rubber inlets on the intake.

Anyone have any experience or know how I could start troubleshooting these?

[ninetres]

Shitty clamp or weld leaking on exhaust. Not sure about intake. CEL seem to be super rare or never at all with Rotofab. Double check all wires, connections, clamps etc.

[superchi]

Originally Posted by ninetres

Shitty clamp or weld leaking on exhaust. Not sure about intake. CEL seem to be super rare or never at all with Rotofab. Double check all wires, connections, clamps etc.

For anyone who comes across this thread (I know there were some stories I saw of guys with SW catbacks that ran into this same code), ninetres was right about the clamp. I was able to resolve the P0420 code by replacing the 2 1/4" exhaust clamp (the clamp at the cat connection) provided with the SW catback with a 2 1/4" lap joint exhaust clamp I got from Summit. Seems to seal much better and have gone through a drive cycle without any codes popping back up.