Step-by-step guide to testing spark plugs with visual inspection, multimeter diagnostics ($15 tool), and live spark tests. Includes symptom charts, troubleshooting tables, and mechanic-approved tips to fix misfires and save repair costs.
Learn critical bad thermostat symptoms car owners MUST recognize (stuck open vs closed). Includes DIY tests, repair cost breakdowns, driving risks, and how to prevent catastrophic engine damage. Don't wait until it's too late!