Q: What are the key steps to follow when replacing spark plugs on Mercury Grand Marquis?
A: Firstly, check the specifications before you replace the spark plugs to make sure that you are using the right ones, allow the engine to cool down before proceeding further, examine the new bulbs for flaws and adjust their gap appropriately, and lastly, take off the wire without breaking anything. In addition, blow out any dirt from the interested hole, pull it out with a socket without hurting any other thing around by mistake and gather some anti-seize compound, then put wire back. Now do this for all of the plugs.