The distributor could be failling, there might not be enough fuel or air reaching the engine (too much is bad too), or your spark plugs/wires are damaged or not to spec.
No it will not cause misfire.
Contaminated fuel could cause a misfire.
It's called a misfire... or random multiple misfire. It can be cause by a number of things. check your spark plugs for fouling, your spark wires for breaks or cracks in the rubber, your distributor, or your fuel injectors... it could be a tricky prob. or it could be easy as pie to fix...
Do a proper diagnosis to figure out the cause of the misfire, then repair it.
Depending on the cause of the misfire, it could damage the catalytic converter.
Terrorists
you either did not gap the plugs to spec or you put this wires on wrong
Water can get in and cause a misfire.Water can get in and cause a misfire.
An intermittent crankshaft sensor will not let the engine fire the correct times. This can definitely cause a misfire for the engine.
P0300 is a random cylinder misfire. Ensure engine is properly tuned.
There are several things that can cause your 2003 or Expedition to misfire. The most common cause is a plugged catalytic converter.
A backfire is caused by a misfire... a cylinder fails to ignite the fuel which may cause a stutter, it may also cause a back fire due to it pushing that un-ignited fuel into your manifold where it then ignites from the heat of the other cylinders and boom you have a backfire...