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.
Air Injection System: Description
The pulse air injection system is used only on the 4.2L engine. System utilizes the alternating positive and negative exhaust pressure pulsations (instead of an air pump) to inject air into the exhaust system. This injection of air burns the unburned fuel in the exhaust system, which reduces the amount exhaust emissions escaping into the atmosphere. System consists of a Micro Computer Unit (MCU), air injection check valve, air control valve, air switch solenoid, and vacuum storage tank.
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.
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