Reoccurring not constant code & check engine light?

[Bfromla]

Yup not constant & little screwy. Currently code P1174 (bank 2 too lean) & check engine light will appear one or other, swap, &/or both but nothing consistent.
Mileage & findings summary:
52524m stalling at low idle,12-1400 red lights & parking lot speeds <5mph even some off ramps slowing to merge.
52945m new fuel filter.
58388m P1175 (bank 2 too rich) & C1290 (VCM)
58401m P1174 (bank2 too lean)
58403m new battery DIY; dealer did new starter, new plugs, & new purge valve assembly.
58411m back to me.
59359m stalls 4~5 times in downtown lights, (not usual route) no codes no check engine light.
59458m check engine light no code. added Lucas injector cleaner.
59488m swaps P1174 & no light.
59492m both.
59500m light no code.L
59503m both maybe a 1/4 tank left running Shell 93 (supposedly ethanol free) & only filling to the pumps auto stop, learned may have been overfilling tank, which is what killed purge valve & began stalls; & of course it didn’t start this till out of warranty.
Any ideas suggestions please, getting oil changed this week. The tech hopefully will see more with buds.