Hi everyone,

I'm new to the Acura world. After owning all three of late 90s model Jeeps, I decided it was time for something faster and more reliable. I bought a 2005 TL 6MT mid-July with 195k miles, and have been battling DTCs since.

First it threw P0161, suggesting a bad oxygen sensor. I replaced the sensor 3 times, twice with cheap eBay parts, and again with OEM. Next, I spent a few hours testing continuity, resistance, and pulling harnesses apart, trying to find any open circuit, with no success.

Now it's showing P0420 as well as 161, with low catalylist efficiency, bank 1. From what I can tell, there are no efficiency or performance issues.
After some research, I found both of these issues can be caused by faulty fuel injectors (the car isn't showing symptoms of this), by leaking exhaust, or leaking air intake.

Does anyone have any thoughts or suggortions? Im hoping there's a common cause for the two, I'm a broke college student :/

Thanks!
Hunter