I recently battled with these exact codes. I chased vacuum leaks finding nothing. The p0441 code is for your purge valve. I found when my purge valve went it wasm t sealing in the closed position, allowing unmetered air into the intake causing lean conditions setting off the lean codes. After weeks of scratching my head I replaced the purge valve, fuel trim numbers stabilized immediately after and no more lean codes. I had done injector orings, upper plenum gasket and all vacuum lines, my bank 2 was noticeably leaner then bank 1 on ltft as well. I replaced with a Bosch purge valve.

 

*MAYBE* fixed-

I replaced the purge valve about a week ago with an OEM Hyundai valve (P/Ns 28910-22030, 28910-22040) and that eliminated the P0441 code. $15.50, shipped (ebay).

Yesterday, I replaced the injector O-rings, as well as the injector filters (baskets) and pintle heads. No codes thus far, but then again I have just had it idle and have not put any miles on it. The idle is noticeably smoother, though, so I think I may have solved my issue. The O-rings that fit into the lower intake manifold were squished, sort of like a flat tire. The O-rings in the fuel rail looked nice and round, sort of like an inflated inner tube.

The repair was pretty dang easy; I'd say it took about two hours. About 30-45 minutes of that was spent finding torque specs for the upper intake manifold, and devising a way to remove the fuel injector baskets.

 

This is what I used to remove the injector baskets. The screw's outer diameter is slightly smaller than the nut's inner diameter.

 

Video of an injector basket removal:

 

Old O-rings:

 

I'm comfortable saying the fuel injector O-rings solved the issue. A couple days after replacing the o-rings, I was getting the following codes:
P0300 (Misfire On Multiple Cylinder)
P0301 (Misfire Cylinder 1)
P0303 (Misfire Cylinder 3)

I replaced the spark plugs and no more codes. I suspect the lean condition created by the failed O-rings fouled the spark plugs, thus the misfire codes. Either way, the codes are gone even after a couple hundred miles on the new O-rings and spark plugs.

 

Great news. Thanks for posting back

 

Glad you were able to solve the problem, looks like ill be changing the O rings as well as my intake manifold gasket which I suspect is also letting in unregistered air. Hopefully ill have the same results.

 

Good luck. It was quite simple and it's cheap, so it's worth a try.

 

Simple might be a relative term...

Thanks for posting your process. I'll be doing the same thing to mine later this week. Prior to rebuilding each one, did you do any cleaning of the injector itself, to be sure you didn't get any crud inside the injector? I have an intake gasket kit coming, as well as the injector rebuild kit. Any other parts I need to make sure I have on hand before I get started?