Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Mark VIII
Each cylinder features 2 intake runners located between intake manifold and cylinder head. The primary runner feeds air to the cylinders whenever engine is running. The secondary runner is opened and closed by the IMRC vacuum actuator, which is controlled by the IMRC solenoid and Powertrain Control Module (PCM). With engine speed less than 3000 RPM, IMRC solenoid is energized by the PCM allowing vacuum to the IMRC vacuum actuator, closing the secondary runner. With engine speed more than 3000 RPM, solenoid is de-energized and vacuum is vented, allowing actuator to push secondary runner open. This system improves low and mid range torque, and improves fuel efficiency.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.