| The reason it will sometimes get better after cycling the key is because the DME (engine module) after detecting a misfire will go into what is called "cylinder cutout" mode meaning that it shuts down the injection for the cylinder which it read the misfire in. So even if the faulty ignition coil or spark plug etc has come back online the DME is still cutting out injection to that cylinder. The reason it does this is to protect the cat converters from the damage that unburned fuel can cause. A cycle of the key will reset the cylinder cutout until the misfire is detected again by the DME.
Make sense?
DT | 
