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.
Idle Speed Control (ISC) (CARBURETED Models)
The ISC is a motor which opens or closes the throttle (in idle position), according to commands from the ECM. The ISC maintains low idle speeds while preventing stalling due to engine load. The base idle speed is programmed into ECM memory and is not adjustable.
When the engine is cold, ECM holds the throttle valve open for a longer period of time to provide faster warm-up. This function is by-passed when throttle is opened enough to bring TPS off its idle circuit.
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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.