MERCURY P CODES (POWERTRAIN) P0300 - P0399

What Is This Error Code(p0306) On A 2007 Mercury Mountaineer? And How Do I Fix It?

I Have The Code P0301, P0302 And P0303 In My Scanner, But The Problem Was When The Catalyzer Burn The Floor And The Mat Of My Car. Please...

Chugs In Overdrive Idles Rough, Throws Code P0302. When I Check Cylinder 2 Plugs Look Good, Light Brown Tinge Color, Put New Plugs And...