Where or which is the Bank 1 O2 Sensor? on a 99 TL

 

its the front O2 sensor. Its located on the exhaust pipe just past where the 2 merge together. the bank 2 or rear one is on the cat.

 

I got the check engine light on my Acura TL 2002 on. I took it to the dealer and he said he replaced my Catylitic Converter with a used one. I drove away and the next day the check engine light came back on. PEP Boys told me that the OBD code was P0420. I also made the big mistake to fill up my tank with regular unleaded gas. Could this be the cause? What else might be wrong?

 

Hope you got a gaurantee on that used cat!
Crappy gas could set it off too, I suppose.
use up the gas get high octane gas and then

I'd try clearing the codes again ....