when you pull off the plug wires while its running the first and second have no effect the third and fourth make it stall, there is spark to all cyliunders and good compression, also getting fuel, any help please
suddenly lost power,it has a bad skip,replaced wires and plugs,no change on 1991 Mercury Capri
SOUNDS A LOT LIKE A VACUUM LEAK THAT IS AFFECTING THOSE TWO CYLS. CHECK FOR A BROKEN OR LOOSE VAC. HOSE OR DEFECTIVE INTAKE GASKET.
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You either have a vacuum leak like wetry told you, or you are incapable of checking your spark, compression and/or fuel correctly.