Since wires, cap, and rotor are new, try cleaning the top of the coil. The usual crud there can absorb moisture and become conductive enough to bleed off the high voltage. Clean the primary terminals too, by taking them on and off a few times.

The coil primary +12v circuit on the MPG ignition is also known to be "iffy" at times. You can safely bypass several junctions with a direct jumper from the Battery Positive to Coil Primary terminal #15 as a diagnostic for "no spark".


--
Bruce Young,
'93 940-NA (current), '80 GLE V8 (Sold), '86 240dl, '85 244 ti, '83 245t
'76 244 (R.I.P at 255k), 73 142 (98K), '71 144 (ex circle track car)
Used '70 144 from '78 to '92, New 144 from '67 to '78, Used '62 122 from '63 to '67