I threw a code a couple days ago and thought that it would be my o2 sensor, so I changed it. CEL hasn't showned up yet so Im guessing its koo, but since the p72 ecu stores the codes thats been thrown I checked it today and it threw 2 long lights. That's the o2 sensor #2, how can that be if I'm OBD1?

 

Code 20 is the ELD (electrical load detector). It's built into the underhood fuse box.