I have been dealing with this issue for a month or so and I can't seem to get things figured out. Any help would be great

2003 F150 Super Crew with 4.6L 131,000 miles

Facts
I am getting P0175 code
showing high negative LTFT on bank 2 (-25%)
lacks power on acceleration
running a little rough
no miss fires shown

Here is what I have tried
new fuel filter
cleaned MAF
Switched fuel injectors from bank 2 to bank 1 with no change noted
replaced 1 bad vacuum line all other seem ok
Plugs and coils replaced about a year ago.
Pulled plugs and tested coils with Ohm meter and everything checked out, plugs looked good, no fouling noted.
Changed forward o2 sensor on bank 2

Not sure what else to look for, about to go crazy trying to sort this out. There is a little start up noise, could this be a timing chain issue? Already went through this on a 5.4L Navigator, not looking forward to this again.

HELP!!

Mark

 

I'm going to make a guess and say check the fuel pressure and fuel pressure regulator.

 

Jgger,

I'll take a look, I pulled the vac line from the FPR and there wasn't any fuel leaking from it. Also, I dont have any starting issue, which usually indicate some fuel delivery issue.