I currently am trying to find the cause of system too lean codes. PO0171 and PO0174
A little history
Purchased last year around April PO171 code showed up almost immediately. Cleaned Maf sensor, and put injector cleaner into fuel. That seamed to clear the code until September. Then the code started showing back up intermittently. Stored the truck until spring. Smoke tested intake over winter and found no leaks. When i started driving the truck a week ago both engine lean codes came back. Added injector cleaner to fuel that cleared the bank 2 (P0174) code but the bank 1 (P0171) comes back. There are no other engine codes shown. I started watching some live values while driving the fuel pressure fluctuates a bit at idle and while cruising at 2000 RPM. It falls to 41psi at times. and then quickly recovers. It does increase to about 55-60 psi under harder acceleration.
Today I removed the spark plugs and the front three spark plugs of bank1 (right side not sure what the cyl numbering is) are white compared to the rest which are a nice light brown.

Im trying to determine if the injectors are partly plugged or the fuel pump is possibly getting weak. It does not run rough or stumble when driving.
Scan tool is a IID tool
2008 Range Rover Supercharged Canadian vehicle