I have a 2004 5.4l 3v with 180,000 miles that all of a sudden starting running real rough Thursday. It ran perfectly fine prior to when I started it up yesterday, it had decent power an I was getting about 17 mpg highway and 12.5 city. But when I started it up Thursday it was missing real bad and the check engine light came on.
The codes are P0175, P0172 and pending P2198 and P0420.
I'm fairly certain that the cat and O2 sensor (stuck rich) codes are a result of what is causing the first two (banks 1&2 running rich) so I believe if I find why it is running rich it will also solve those.
So far I've come up with the possible problems being MAF sensor, stuck fuel pressure control module , injectors, or cats.
I am thinking the fuel pressure control module is the most likely culprit as I went off roading Saturday (the last time I drove the truck) and it most likely got very wet through creek crossings. And it seems very unlikely that an injector on both sides would go bad at the same time. I also think it is that because it was so all of a sudden. Any ideas?