As they say, $hit happens!!!!!!!!!
Since my early days of driving cars with points and condensors, I learned (the hard way) that after a tune-up and the car still ran like crap, I could have installed defective parts, so I made it a habit of starting the car with out the air cleaner after dark, just to check for spark arcing..........You'd be surprised at how fast those old factory plug wires go bad..........to this day, I still start and check my car after dark for that very reason..........
David