High secondary resistence,(bad plug wires or plugs) will cause the secondary voltage to eat away at the primary insulation in the coil. Eventually the high voltage will make its way into the primary circuit and back to the pcm. This will anger the pcm gods and they will shut down the asd relay. The fix is to replace the coil, plugs & wires and maybe the pcm. If your mechanic has a scope, he should be able to see the high voltage spike leaking into the primary circuit.