car: 92 civic cx
engine: 92 b17a

problem: got it up and running yesturday, everythign went fine, went for a ride, everythings still fine, came back to adjust the throttle cable, did that, and then I plugged the idle vaccum thingy, and we assumed that some how caused the CEL light to come on, we checked the code, code 43(fuel system too rich or too lean), reset the ecu, drove it for like a day, no problem, tonight, CEL comes on, its code 43 agen, what can be causing this? he has a stock cx fuel pump, used the civic cx fuel hose(from fuel filter to fuel rail[I know its smaller, but its the only one we had]), still has stock civic cx fuel filter, can any of that be causing the problem, if not, anyoen have any ideas at whats causing it?

 

It is your O2 sensor. 99.9% of the time code 43 comes up is because of a faulty O2 sensor...
Install a new one and you should be good to go.

Later,
BR