Provides high quality tools to get the job done right. Spark plug misfires occur when the sparks jumping the electrode gap are inconsistent in timing, causing the engine to stumble or lose power. Heavy-duty construction: Made only with materials that let you test whether your spark plug is functioning properly. This helps save time and money by confirming whether the problem is actually in your ignition. This handy compact tool helps you view the gap in the spark plug tester to determine whether you have inconsistent timing or not. The spark plug tester is manufactured exclusively from the highest quality materials and works on spark plug connections, diagnosing spark or ignition failures, defective contact points, bad cables, and much more. Use scenarios - Diagnosing a vehicle that hesitates or loses power to determine if the issue is caused by the spark plug, ignition timing, or related components. - Performing routine maintenance checks in a repair shop or DIY garage to verify spark plug operation before road trips or seasonal service. - Troubleshooting misfires by testing spark plug connections, ignition wiring, and contact points to quickly identify whether replacement parts are needed.