Lean fuel codes

[2003bmtf150]

My '03 F150 has 2 DTCs...0171 & 0174; banks 1 & 2 lean. At 122222 miles and periodic fuel injector cleanings, is it time to check their flow or consider replacing 'em? Maybe I should look @ the fuel pressure @ the regulator, or look @ O2 sensors? Used Seafoam in the fuel tank a few times, as well as another cleaner. The codes clear but set again after 50 miles or so. Any suggestions or recommendations would be appreciated.

 

[blacksnapon]

I believe I'd be looking for a vacuum leak. Get some carb spray and spray it around the intake manifold, pcv valve, brake booster, and vacuum lines while its running.