I'm getting a code 43 and cant figure out why? My engine runs fine until the computer goes in closed loop mode. Once it warms up it sonds like its missing from 1000 to 3000 rpms. I checked the wire going to the knock sensor and it was fine so I replaced the sensor. That still didn't fix it. Anyone have any ideas what is causing it. Its a 1990 Fb w/ a 3.1 in it. The wiring harness shrted out and caught on fire a while ago but I replaced all the burnt wires. Could the ecm be messed up? Also when I try to set the timing the engine only runs somewhat right with the timing advanced 20 degrees. I'm getting ready to replace the harness and ecm b/c i cant figure this out.

 

I shoot for the ECM it may have been tosted during th fire. Then I would aftr thw wiring harness.

Does any one know how hard it is to the wiring harness? Most of my wires are prety stiff and worn.