Depending the year and type of car it could be a ballast resistor
you could have a bad coil. no power to the coil or possiballya bad cap and/ or rotor bug
If you do not have a key the coil is not going to spark.
Hey Tia== Make sure they are replacing it with the correct coil. Then have them check the voltag going to the coil . It should be about 8 NOT 12volts. It has a resistance wire cutting down the voltage. GoodluckJoe
Chase the sparkplug wires back to the coil pack. Depending on the size of engine is going to determine how many wires there will be. Keep in mind where you unplug the wires from the new wires will need to go back the exact same way to keep the firing order the same.
A bad ignition module.
Make sure you have only about 8 volts going to it not a full 12. There is a resistor wire that should cut the voltage.
Carbon buildup can keep a motor from firing and cause an engine to stall.
Firing as in starting and running, no.
Check the coil and replace if bad. Should fix the problem.
no it does not keep milk from going sour and if it did why would you put it in your milk.
Once you've already started i would say keep going.
It could, along with many other parts.