Hey I have a 2008 Ford Focus SES with a automatic transmission. The 4th cylinder is miss firing my wires are good and sending power I just put new spark plugs in and got new ignition coils and it still miss fires. But here is the kicker with a cold start it runs just fine. But if I turn the car off and back on when it's at running temperature the piston begins to miss fire. Any ideas guys please help because this is really annoying also I check my fuel injection is work fine as well.

 

On further inspection there is oil running down the side of my motor this would explain the belt sounds and compression loss

 

If you determined the cause and know what to do for it ,great.

If not, you need to be more specific as to just where the oil is leaking. Is it coming from the #4 area?
Which engine is in the vehicle?
What else have you done/checked?