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.
1988 Toyota 4Runner Base, AutomaticFACTORY OEM SERVICE PROCEDURE
Land Cruiser
- Disconnect air by-pass hose from ASV, which goes to silencer. Note engine coolant temperature and start engine. At idle RPM and with coolant temperature less than 50°F (10°C) or greater than 104°F (40°C), air should be present at ASV hose nozzle.
- At idle RPM and coolant temperature between 59°F (15°C) and 95°F (35°C), air should not be present at nozzle. Increase engine speed to 3000 RPM with engine coolant temperature between 59°F (15°C) and 95°F (35°C). Air should now be present.
- If test is okay, system is functioning properly. If test fails to perform properly, proceed and check individual components.
Factory Service Tools
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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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