This diagnosis is typically intake manifold temperature drift (high box).
87.4.1
Intake Manifold Sensor Check
Check as follows:
1. Disconnect the Intake Manifold Temperature Sensor.
2. Inspect the Intake Manifold Temperature Sensor connector for bent, spread or corroded
pins.
[a] If connector damage is found, repair as necessary. Refer to section 87.4.1.1.
[b] If no connector damage is found, replace the Intake Manifold Temperature Sensor.
Refer to section 87.4.1.1.