1992 Lexus ES 300 1992 es300 low power

I recently bought the neighbors 1992 ES300. Had a blown head gasket on the front bank. Replaced the gasket, had the head checked and milled. Checked compression, 180 all the way around. MDrove away from the house and noticed it was way low on power and smells like its running extremely rich. I changed plugs, cap and rotor, engine temp sensor, fuel pressure regulator. I noticed that after driving 20 miles, the plugs on the back bank(cylinders1, 3, 5) have a nice shiny coat of carbon on them, black as coal. The front bank, (cylinders 2, 4, 6) look new. I thought maybe a o2 sensor. I switched the front o2 sensor to the back and then put a new one on the front. Even tested the voltage through the diagnostic port under the hood as the manual suggests. No change. Starts fine, sounds decent. As the engine warms it runs poorer but still runs, barely, no power at all. The only thing I can think of that would only affect 1 cylinder bank would be the o2 or the ecm. Am I missing something?