Misfire in 2 and 6

MustangLX-5.0 said:

You sure the crack in the head sealed properly? Those additives don't always work depending on the size of the crack.Was it an external crack ..or internal? Does white smoke blow out the exhaust? If so,that would indicate coolant getting sucked into the combustion chambers.

Cylinders 2 and 6 are on the same coil.Let me explain the coil pack a little just so you get the idea of how this works.The coil pack has 3 individual coils,not 6.Each coil controls 2 cylinders.Standing in the front of the engine,looking at the far left coil.The upper left is cyl. 1.The one below it is 5.Next over "2 - 6" then last "3 - 4.When one cyl. fires, the one below or above it fires but with about 1/4 the energy.It has to do with emissions and burning off residual fuel.

Now that you possibly understand,you obviously have a problem with that coil pack.Cyl's 2 and 6 are both on the same coil.BOTH are not firing or firing only part of the time.To me it sounds like they aren't firing at all with the severe lack of power you describe.Does the car shake a lot when it's running?If it does then it is definately missing 2 cyl's constantly.It is very possible that you got a defective coil pack.Where did you buy it? It wasn't Autozone was it? If it was,return it for cash and buy one at Advanced Auto or PepBoys.

Injectors don't usually "break".In rare instances an injector solenoid can get stuck open or close.This can be caused by excessive deposits or even a defective unit.Doesn't happen all that often.The most that can happen with injectors is that the nozzles get fouled up with carbon deposits...oil or other debris.This can cause too much or too little fuel to be sprayed into a cylinder.An extremely fouled or plugged injector can cause the same symptoms as a non-firing spark plug.

One other cause is that you have more than just a simple crack in the head.Did your engine overheat and cause this? You should run a compression test on all 6 cylinders to rule out loss of compression.A crack at or near a cylinder or combustion chamber will cause very similar engine shaking and mis-firing as a bad spark plug or fouled injector.

Last,make sure that you cleared all old codes from the computer after you did all that work.Old codes will still show up in a scanner regardless if there's a problem or not,until the memory is cleared.

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