Lean condition bank (1) bank (2)?

1999 Firebird 3.8. I have lean OBD II codes a rough idle and poor acceleration. I have changed spark plugs, wires, ignition coils, MAF sensor, front two O2 sensors (I did not change the back one because I thought that if the front two were bad I should only have a bank (2) lean condition but even after replacing the front two the codes came back, though the car felt like it was fixed for a couple of days...weird) and I also cleaned my throttle body ( I can't replace the TPS, you have to replace the whole throttle body, though I can hear the sensor click over when I shut off the car) My only other guess is fuel injectors. Fuel additive doesn't seem to help, is there a way for me to test my injectors? Do injectors seem likely? It all stems from a spark plug wire that shorted to chasis a long time ago, once I fixed the Mis-fire I ended up with this problem. Please help.