I am having the same exact problem, I have the same rig and installed the same injectors this last weekend. I am now getting a bank 1 lean code and a rough idle with LTFT at 25. I did not replace my distributor/cap/rotor but mine are not very old and looked pretty good upon inspection, I know sometimes they have issues you cannot see but I do not expect them to be my problem. I also didnt initially replace the upper plenum gasket, I am considering that now. I also have recently replaced my MAP, IACV, EGR, TPS, Air Filter, Mass Airflow, PCV, upstream 02 sensors (CATs removed), Fuel Pump, Fuel Pressure Regulator, spark plug wires, fuel filter, and probably some other stuff I missed. I would like to pick up where this thread left off and try to solve this issue so when CTX-SLPR gets back maybe we can have an answer. I love this suburban and would love to get it back to running the way it should. I am going to take the plenum off again and see if I can tell which injectors may not be seated properly. Any advice would be much appreciated.