Are you sure the ECT (engine coolant temp) sensor is reading correctly? Was
the thermostat re-installed? Low temperature will cause extremely rich
mixture. The ECT overrides oxygen sensor, mass air flow sensor and all other
inputs. Plug in a scan tool and see what the warmed-up temp is and if the
ECM is in closed loop before you do anything else.
Chino Autotech Inc.
← Counterpro Q/a