Engine Crank/Engine Running
WARNING: This page does not describe the selected car, but rather 32 other vehicles, including the 2009 Mercury Mountaineer, 2009 Mercury Milan, 2009 Mercury Mariner, 2009 Mercury Grand Marquis, and 2009 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
During engine crank the PCM fires two spark plugs simultaneously. Of the two plugs fired, one is under compression while the other is on the exhaust stroke. Both plugs fire until camshaft position is identified by a successful CMP sensor signal. Once camshaft position is identified only the cylinder under compression is fired.