Spark plug reading chart showing 30 used plugs labeled from oil…

Spark Plug Diagnosis (I can't remember where I found this, but I didn't create it)
IF THE IMAGE IS TOO SMALL, click it.
The inside back cover of any Haynes manual is another source for this info.



5.8L MotorCraft SP-415, SP-501
5.0L MotorCraft SP-450, SP-502
4.9L MotorCraft SP-435

Spark plug & coil wires should measure ~7KOhm/foot from the terminal inside the distributor cap to the terminal in the boot that slips over the spark plug.



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See also:
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Owner caption January 2022 · Photo 0 of 5000