Hey guys, I have a 2003 v6 mustang with 200,000 miles on it. It has had a p04555 engine light on for a while now. A while ago it had the "check gas cap" light on so I replaced that with an OEM cap and it turned off, but then the engine light turned back on after a few hundred miles.
It has been getting worse and worse gas mileage the past few weeks, and it will idle really rough when I first start it up. Even when it's warmed up and I start it up, the engine runs really rough.
It also has a...

P0455 code, bad gas mileage, gas smell