So I've got a 1989 Si with a single cam OBD0 ZC swap, PM6 ecu. Constantly throwing code 1, oxygen content. Tried multiple o2 sensors, Denso brand. Replaced distributor with a Richporter unit, no change. Tried 2 PM6 ecus, no change. Can't seem to figure it out. Car runs fine until it throws the code and the CEL comes on, then is real boggy. Flip the key to off, then back on, runs like a champ until it sets the code again. Rinse and repeat. Also dealing with a surging idle when cold. Pulling my hair out, I feel like I've been through everything and have come up with nothing. Any help is greatly appreciated. Charcoal can was deleted, not sure if that affects anything.