Lean fuel Bank 99 Suburban

Looking for help with 99 Suburban LT. Occasional no power on acceleration, constant engine light. Engine light code reads lean fuel banks, replaced both filter and pump which did not correct. Disconnected Mass Air Flow sensor, which corrects acceleration problem but provides terrible gas mileage. Mechanic says that it could be Air Flow sensor or computer problem, but both would be guesses. Any other similar experiences with this? After vehicle warms up and gets to 20 mph, it runs perfect. Never know when it will act up so hard to pull out into traffic not knowing if it will have power. Problem comes and goes, one day its there, next day it acts up, but is getting to be more common than not.

Well by richening the engine in the default situation created by maf disconnect, you are solving the lean mixture, try cleaning the maf, also, scan it and see if it shows proper air flow.