Intake Manifold Runner Control Stuck Open (Bank 1)
The intake manifold runner control (IMRC) flap on bank 1 is stuck in the open position. The IMRC swirls or tumbles intake charge at low rpm by closing one runner per cylinder; when stuck open, low-end torque drops and the engine may misfire on cold starts.
Affected components
- Intake manifold runner
- Imrc actuator
- Intake manifold
Common causes
- High likelihood: Carbon buildup blocks flap travel
- Medium likelihood: IMRC actuator or vacuum motor failed
- Medium likelihood: Linkage rod broken or disconnected
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.