Engine Crank/Engine Running
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2005 Mercury Sable, 2005 Mercury Mountaineer, 2005 Mercury Monterey, 2005 Mercury Montego, and 2005 Mercury Mariner. However, it is still accessible from the selected car via links, so may be relevant.
During engine crank the PCM will fire 2 spark plugs simultaneously. Of the 2 plugs simultaneously fired, one will be under compression and the other will be on the exhaust stroke. Both plugs will fire until the camshaft position is identified by a successful camshaft position (CMP) sensor signal. Once the camshaft position is identified, only the cylinder under compression will be fired.