Hey, I own a 2003 MCS, and had just done some recent performance upgrades to it such as a 17% pulley reducer, intake, bypass valve, short throw kit and exhaust.

after i installed the pulley, bypass and intake, my SES light came on and the code said it was running lean. I cleared the code and then another came back saying it was the o2 circuit, bank 1, sensor 2.
does anyone have any information or has had the same problem?
Just want to try to get in the right direction to fix it.

Thanks!!