In my girlfriends 90 si, it has a zc motor and ecu. it has been throwing a cel for a while. it was always 1, the o2 sensor, but it drove fine so i figured worry about it later, the tach has been jumpy lately too, but i thought maybe that was due to the aftermarket autometer tach. Well the other day it ran like crap stutter, etc. and threw codes 1, 3, 4, 7. well i got it home let it sit overnight. and it drove fine to the shop next day. i rewired a new o2 plug(off of dx harness) because i thought mine was bad due to a/f guage etc, replaced all but-cnnectors with soldering, also redid the two extra cam poisiton sensor wires that i lengthened when i did the swap. i did all that , reset the ecu and a day later the only code to come back was 1(my a/f guage also hasn't worked since i resoldered the new plug), but it drove perfect for a week. then it happend again!! this time codes, 1,3,4,7,8 so i took it too her house tried a old o2 sensor cleaned the plugs and check the cap rotor etc, all looked well but i took some time to make sure all teh connections on the sensors were good in the distributor. reset ecu and drove it, drove awesome but i still have cel 1 again.
I have no idea if i fixed anyhitng or not!! does this sound like two seperate problems, o2 and dizzy?? or could a bad o2 or o2 wiring throw the mixture off that much causing all the other problems, my spark plugs and o2 were so black after my short drive home in the sputtering. i'm going to pick up a new o2, and i'm going to run a jumper wire for teh o2 to the ecu just in case there is a break some where, but other than that i have no idea!!!! any helpo would be appreciated!!!!