Don't have all the details but there's a Lancia next door in the garage that won't keep a stable CO reading UNLESS you disconnect the air intake temp sensor in the manifold. Replaced the sensor but still no joy.
Check for fault codes on the ECU. Check what reading the sensor is giving the ECU, via the ECU if possible otherwise by measuring the resistance across the appropriate pins of the connector with the ECU disconnected.
......they never learn.
glad you sorted it.
