Please choose the correct ending to complete the given sentence: Cars & Other Vehicles: [header] How to replace your mercruiser spark plug wires [title] Read your manual and all the safety tips. [title] Read all warnings about fuel, fuel vapors and dangerous moving parts. [title] Understand that you are working with explosive vapors and sparks so extreme caution must be taken to avoid explosion and or fire.

Ending1: [title] Clean the spark plug wires thoroughly if the have been exposed to gasoline. [step] If this was the case, you will need to clean them thoroughly because now carbon dioxide is in the engine, it is more dangerous and should not be cleaned on the spark plug wires. Ending2: [title] Determine your engine rotation (see tips). [title] Write down your firing order for your model engine. Ending3: [title] Wear a contact cap and gloves when working with active spark plugs that have been threaded incorrectly. [step] A wire against your head should show you clearly what type of ignition you are doing. Ending4: [title] Map your vehicle to make sure there are no obstructions or technical dangers. [title] Locate your power supply and the spark plug wire that holds your battery.

Answer format: ending1/ending2/ending3/ending4