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AV-SCANNER / Accessory guides / Engine and fuel
This workshop guide covers the complete use of a spark plug socket and gap tool for removing, gapping and refitting spark plugs on gasoline engines. It is written for motorists who service their own vehicles and for working mechanics who want a disciplined, repeatable procedure. You will learn how to select the right socket and gap tool, set plug gaps accurately, read the results from plug condition and gap measurements, and diagnose common misfire and driveability faults. By the end you will be able to carry out a full plug service safely, calibrate your tools and recognise when a job needs professional attention.
Guidance is general and covers many makes. Exact procedures and values vary by model, so confirm them in the factory service information for your vehicle.
Download all 12 sections as a branded PDF to use in the workshop.
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