My 1976 Lincoln Mark IV died while running recently. I replaced the fuel pump a little while back and it ran great after replacing that, but now it won’t turn over again. My neighbor who is a retired mechanic suggested I check the ignition system, since the fuel system is probably in decent shape.
While checking the resistance on the ignition coil, the secondary resistance seems to fall in spec reliably, but the primary resistance seems to vary wildly. It will register in spec for 5-10 seconds at a time and then the resistance will shoot up to 40 ohms+ and then jump around and it usually returns to spec. This seems to happen more often if the coil is titled while measuring, but that could be a fluke.
Does this suggest the coil should be replaced?