cylinder missfire issues

[fernandez99]

I have an 03 Expedition with a 4.6 I keep getting a "no 8 cylinder missfire detected" code with an occasional "bank 1 and 2 running lean code" I've replaced spark plug, swapped out ignition coil, verified spark on coil, swapped out fuel injector, I'm at a loss... car still runs rough and bogs down, obviously running on 7 cylinders... any suggestions?

 

[ELVATO]

Did you disconnect the battery after every test (swapping coil, plug, etc)?

 

[fernandez99]

No I just cleared all codes and started engine.

 

[ELVATO]

Try swapping the coil, then disconnecting the battery. It should clear the code and "reset" everything.

 

[fernandez99]

didn't fix it I may have to taker her in to a mechanic. Is it possible the combustion chamber is fouled up? when I pull that plug out its contacts are black and gunky. If that's the case, how do I clean that without stripping down the heads? Are there any products out there that work to clean fuel system?

 

[Reconracer]

Having a similar issue...try a can of Sea Foam to clean up fuel system. ELVATO mentioned in my thread that the wires to the injector / coil may be damaged. You may want to look into that.