I have a Subaru Outback 2011 2.5 Limited which has been showing a P0171 Bank 1 System Too Lean code for weeks now. I have tried the following to fix it: replaced fuel pump with OEM Delphi pump/filter assembly; replaced the MAF; replaced both O2 sensors (before and after cat converter); replaced all 4 fuel injectors; replaced spark plugs. But still have the P0171 even though the car seems to run fine. One thing I noticed was oil on the front spark plug on the bank 1 side (left side). I’m considering changing the cat converter itself but I have also read about oil meaning a gasket leak. Also, a lot of guys seem to fix this with a vacuum hose change? I don’t know and I’m not a mechanic. But I am fairly handy and I can usually figure it out and do the work ... I’m stumped and I’m tired of guessing. Any ideas?