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.
1990 Lexus LS 400FACTORY OEM SERVICE PROCEDURE
Throttle Controls (LS400): Dashpot
- Start and warm engine to operating temperature. Remove cap, filter and separator from dashpot. Raise and hold engine speed to 2500 RPM.
- Plug small hole in back of dashpot with finger. Release throttle. When throttle is released, engine speed should be 2000 RPM. After a few seconds, engine should return to idle.
- If dashpot does not function properly, try adjusting using a wrench. If dashpot still will not function properly, replace dashpot.
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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