Fuel banks 1, 2 rich, random misfire
 

2000 blazer ....I am going to make another attempt at this. After a year now I still have the same issue. Codes fuel bank 1 and 2 rich and now a random misfire. Somedays when I drive it, it runs fine. Most days it spits and sputters and struggles to get down the road. It seems like when I hammer on it it does better, not perfect..If I hold it steady or take off from a stop steady it sputters and kicks. It was worse when I got it but has lined out some with these parts...I still drive it everyday. ( note that the check engine light goes off and on randomly, runs like crap either way)
New distributor, cap, rotor, plugs and wires, Fuel pressure regulator, Fuel filter, Intake gasket (was leaking). all new vacuum lines, cleaned mass air flow sensor, fuel pressure checked at about 5 pounds low. Mechanic said that he didnt think that would do it because its running rich. Also was told to throw parts at it, again. Maybe o2 sensors, maybe fuel pump, maybe mass airflow sensor, maybe catalytic converter. I have way more money in this thing than its worth now...really don't want to throw parts at it...anyone else ever have this issue and what lined it out?