02 stratus, 3.0, Code PO171, Lean on # 1 bank? Could this be something "other" than injectors?

code p 0171 refers to system too lean bank 1===causes --intake/exhaust leak---AIR system---MAF/VAF sensor---fuel pressure/ pump/ pressure regulator---injector/s---heated oxygen sensor (HO2S unit in the exhaust manifold or before the cat converter
If the engine is running well then consider replacing the HO2S unit as that reports to the ECM that then adjusts the mixture for that bank by altering injector amounts and timing
all the rest affect both banks but the code is bank 1 specific

System too lean, bank 1.

code p0171 refers to system too lean bank 1===causes ---intake /exhaust manifold leak---ARI system--MAF/VAF sensor--fuel pressure /pump---injector/s---ECM
code po172 refers to system too rich bank 1===causes --intake blocked---EVAP canister purge valve---fuel pressure---EGR system---injector/s---HO2S

it could be the o2 sensor or the throttle position sensor .

bank 1 is the side of the motor cylinder 1 is on.there fore bank 1 sensor is the sensor in the exhaust that comes off of the head wear cylinder 1 is.

CODE PO171 FUEL TRIM BANK 1 MIXTURE TOO LEAN. POSSIBLES CAUSES, INTAKE AIR LEAKS, AIR FLOW SENSOR 1, CLOGGED FUEL INJECTOR, EXHAUST GAS LEAKS,INCORRECT FUEL PRESSURE CLOGGED FUEL FILTER, LACK OF FUEL FAULTY FUEL PUMP,FAULTY MASS AIR FLOW SENSOR,INCORRECT PCV HOSE CONNECTION.

More than likely bank 1 sensor has a possible vacuum leak, or a lean misfire on that side of the bank.(lean misfire happens when gap of spark plug are exceed due to wear), As for the 02 sensor I agree that it is reporting the true engine condition on that side of the bank

Code Po171 indicates a lean condition on cylinder bank #1 of the engine. This is the drivers side of the engine. I would suggest replacing both front oxygen sensors as a pair to start. An oxygen sensor has a life span of about 5 years and yours are now 9 years old if they are original. When they get older they are slow to respond to changes in the oxygen content of the exhaust and can trigger a code Po171. If you continue to have the same code set after the replacement of both oxygen sensors then it is time to find out why your engine is running lean. Some of the most common causes are an ignition misfire and a vacuum leak. I have also seen Fords EGR flow sensor (known by Ford as Delta Pressure Feedback sensor) to cause problems like that as well. A good mechanic with a scan tool can usually spot a problem like that in a few minutes.

This can be caused by a faulty mass air flow sensor

That's an 02/oxygen sensor code means that bank 1 or 2 is too lean. Good Luck contact if you need more help.