Report: Crossed Oxygen Sensor Wires Can Cause Poor Idle Quality/Fuel Economy
Ford Aerostar Problem
Exhaust & Emissions Affected: 4.0L V6
If you experience poor idle quality and fuel economy (and the Check Engine Light illuminates) after the exhaust system or motor has been removed and replaced, it could be that the oxygen sensor wires are crossed at the rear of the motor. Wiring schematics should be checked to ensure that the correct harness plug is connected to the corresponding sensor.