I don't think a clogged fuel filter is the cause of the Lean at idle DTC. More likely a vacuum leak, which really only effects the air-fuel ratio at idle conditions.
To see if the PCV valve/regulator is the cause of the Lean DTC :
Try this:
1) Remove the plastic top-engine cover (Pull straight up). The PCV valve/regulator is the black plastic hockey-puck looking thing mounted to the top of the metal valve cover.
2) AT the intake manifold, squeeze together the two plastic clips on the end of the black plastic "S" shaped hose (has a foam sleeve on it) that connects the PCV valve to the black plastic intake manifold. Let this hoes end dangle free.
3) Get a rubber cap and a hose-clamp that will fit the now-exposed nipple on the intake manifold (find at an Auto Parts store, or Home Depot, or Lowes). Seal the nipple with the cap and hose clamp, don't overtighten (plastic)
4) Clear the DTC codes.
5) start the engine, see if the code comes back. You can drive around a little with the hose off...it's just like a VTA (vent to atmosphere) PCV modification). You might get some oil mist and water drops out of the end of the open hose.
6) If the Lean code does not come back, the PCV valve/regulator is defective, replace it.
Another way to troubleshoot :
1) Pull out the dipstick and get a vacuum guage hooked-up to the top of the dipstick tube. Might need to kludge together some different sized vinyl or rubber hose pieces to adapt the diameter of the dipstick tube to the smaller diameter of the vacuum guage nipple.
2) Start the engine, let it idle. If the vacuum gauge reads more (more negative) than about 1 inch Hg of vacuum, your PCV valve regulator is defective, replace it. There have been instances where the rubber diaphragm (under the round cover) tears, which then allows full manifold vacuum in the crankcase, which pulls in more than the usual amount of unmetered air ( causes lean condition).
From other posts, I also think that a leaky enough rear main crankshaft seal can admit enough air into the crankcase, thru the PCV system, to cause a lean idle DTC. (and an oil leak too).
read this :
http://forums.vwvortex.com/showthread.php?5924997-TFSI-oil-leak