2014 LR2 102k mi. - 2.0 Ecoboost

Bought this recently for my daughter and going through it doing a ton of preventative maintenance (rather necessary or not).

I'll start with the issue posted in the title. Fuel system seems to be gasping, periodically hear what sound like a vacuum relief. Thinking may be a bad filler cap, took it off and replaced. With cap removed sounds like a lot of gurggling going on down the fill neck. I recently had the intake manifold off to walnut blast the valves and replaced the PCV Oil Seperator while in there. Any chance the oil seperator is linked to the issue im having? Or is it possible the vent house is blocked on tank? Or could it be the HPFP or LPFP in tank??? At a loss and thought before throwing parts at it I'd bounce it off the folks in this forum first.

Second issue I'm now dealing with is a grind/ratlle sound coming from left rear, only when turning hard to the left from a stop. Sounds like a rattling heat shield, but all are secure. I'm sure it has to be something tied to the rear diff/CV axle. I'd did a rear diff rebuild as it had a bad pinion bearing. Was sure I did the job correctly until I heard that noise. Thoughts???

Other work done:
Replaced Plugs/Coils
Exchanged ALL Fluids (engine oil, coolant, brake fluid, tranny fluid, front diff, Haldex and rear diff)
All new calipers, rotors pads and brake hoses (calipers only because I had them painted)
Replaced belt, tensioner and idler pulley
Walnut Blasted carbon on valves and replaced PCV oil separator and intake seals
Replaced air and cabin filters
New wipers and battery
New tires
Full Haldex service
Rebuilt rear diff
Replaced front diff (xfer case); had a bad pinion bearing also

Still have a bearing sound coming from front. Not sure if the replacement xfer case has a bad bearing or maybe it's a wheel bearing? Is this a common failure?

Any other thoughts/suggestions?

Thx all!

 

Forgot to add that code P06B7 began popping up at same time.

 

Just removed the intake manifold again and went through and rechecked everything. While there, replaced the #2 knock sensor to rule that out. All looked good. Thoughts on evap canister or solenoid???

Update: Whatever may have been wrong seems to have been corrected with the removal of the intake system again. No more gurgling with cap removed or gasping with cap on. Still not exactly sure, but fingers crossed its resolved...