P0171/4 and high fuel trims are usually fuel delivery (pump, filter), vacuum leaks, or sensors. With high mileage cars it can often be all three.
As mentioned above, high trims at idle suggests vacuum leaks (for the reason mentioned), higher trims at high revs suggests fuel delivery, because of progressive starvation as the engine demands more. High trims at both suggest sensors. But these are just directional.
There are certainly other causes - harness and connector issues, bad DCM, and bad gas/ethanol, but the three above are much more likely.
If you have these codes and/or high trims, you really should start by testing fuel delivery, as it is not hard. Low pressure is a failing pump, inability to hold pressure is filter. Then I recommend completely refreshing vacuum hoses, boots and gaskets. These cars are old and it can be silly to do one piece here and there. Once you have done this, do a smoke test or have one done professionally.
Finally, the sensors. You can't evaluate a MAF based on point in time reading. I suspect without more sophistication it is hard to test at all unless you can get a new MAF, plug it in, wait for adaptations to reset and adjust, then compare. O2 sensors can be evaluated if you have a known good sample dataset. When they start going they respond slower, which can be seen in a graph. My advice for the usual 150k+ miles crowd is just replace the MAF and precat o2 sensors.
If I were in your shoes I would replace the vacuum hoses, including the SAP and the hose that connects to the fuel filter. I would replace the dipstick o-ring, the DISA gasket, and the idle control valve seal. And I would replace the intake boots. I would at least inspect the other o-rings and seals for the injectors and sensors in the manifold. The combination of age and intermittent use has likely compromised it all. And replace the CCV if you haven't.
Rubber and plastics decay with heat, sun, and age, not just mileage. And your car is old.
And do a fuel pressure test. It is just not hard to do.
