my o2 sensor warning light has come on when i had the stock D15b2 in my 88 crx dx and it still comes on even after a sohc zc swap. I checked the fuel supply system (fuel pump, fuel filter, and fuel pressure regulator) how the manual says to do it and they checked out. I changed the o2 and when i did the old one's probe was very black which indicates mabye running rich and you can smell the gas when the engine is revved. I have also gone through three sets of used injectors that i had lying around and still the same problem. It only throws the code when the engine is warm and i am either at a steady rpm (cruising) or getting on the throttle and when i turn off the ignition and turn it back on it goes away.

If you have any suggestions i would really appreciate them.