I wanted to give you guys an update on my car. I pulled the air filter and it wouldn't pass the light test if you were holding it against the sun. It has the Chrashler logo on it so could it be...an original air filter with 90K on it? Also, I checked my trouble codes and got 51 twice (why twice?). I know that means O2 sensor but does that mean I need to replace both of them? At $65 a piece that runs into some change.