Mechanics

CHECK ENGINE LIGHT

Ford Expedition

I have a 1998 ford expedition.A few months ago it would run rough and the check engine light would come on. This problem was intermittent though. Now its constant. The trouble codes read misfire on cylinders 3 and 8. Replaced the spark plugs and wires. No difference…the spark to those cylinders seems strong and consistant. Any ideas. Thank you.
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Kodos
July 26, 2007.



Hey man. Thats coil on plug. How can u see the spark. Thats not a convention distributor single coil system.U puliin my leg right?

Tiny
Kin chan
Jul 26, 2007.
No coil on plug. Coil packs.I can pull the plug wires off while its running and the spark is very strong. And my timing light reads exactly the same rpm on all 8 cylinders.

Tiny
Kodos
Jul 27, 2007.
U do that on a late model GM car n u gonna buy modules and coils. Dont ever pull ignition cpts off while engine is runnin on a late model car. Its got a spark but not conclusive. Becuz it imake a spark in atmospheric condition. Inside the combustion chamber it is hundreds psi of pressure. Coil on plug is coil pack. Most ford has problem on coil pack for individual cylinder misfiring. Swap coil and chk if the indivduals misfire change to another cyl. From a suspectible bad coil.

Tiny
Kin chan
Jul 27, 2007.