Looking for some help on a couple codes. Backstory: Had 4 codes initially, Cyl #4 misfire(P0304), misfire w/ low fuel, post cat (P2096). and Knock sensor (P0326). Post cat code was there for a few thousand miles without any performance issue.

Got the Cyl #4 misfire and went into limp mode. did all checks and found bad coil. Changed coil, all wires, and injector o rings. Went a bit further and swapped in 15% WMW pulley, new belt, and colder plugs. After I did all this the car has a slightly rough idle. seemed like idle was much smoother before. not sure if this is normal for a smaller pulley?

I typically use a bluetooth OBD dongle with the Torque app to clear codes. Tried to clear the codes and they would not clear. Did some research and found Foxwell NT510 can clear some codes that others can't. With this I was able to clear out the misfire and misfire w/ low fuel codes. So now I am back down to P2096 and P0326 and a slightly rough idle. Engine runs great otherwise. hits redline without issue. Looking for some advice on these last two codes now. Bad cat and exhaust leak seems like potential causes based on these forums. Anything I can check with this fancy OBD reader? O2 sensor voltage readings perhaps?

 

Bump...