How do you know the wires are good? Don't assume that because they're brand new that they're good.

After you do jw51's test, and find a cylinder that doesn't cause a change in the way the engine runs after you pull the plug wire off, replace that wire with a spare or switch the wire with one from another cylinder and see what happens.

I have seen perfect looking plug wires be the source of a misfire due to an internal crack or some other invisible problem

1950 Chevrolet 3100 (Ol' Roy)

1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)