On record test, with the key-on-engine-off, with the engine cold, look at coolant temperature sensor reading. It should be close to the outside temperature. If it's way off, the sensor is bad. If it thinks it's Winter when it's Summer, it'll cause rich mixtures. If it thinks it's Summer when it's Winter, it'll cause lean mixtures.
On record test, with the key-on-engine-off, with the engine cold, look at coolant temperature sensor reading. It should be close to the outside temperature. If it's way off, the sensor is bad. If it thinks it's Winter when it's Summer, it'll cause rich mixtures. If it thinks it's Summer when it's Winter, it'll cause lean mixtures.
This is B/S