Spark plug, coil arcing

Hi there, I have a 1986 Chevy Celebrity wagon base model. It has the 2.8 V-6 2-barrel carb. I've owned it since October 2015. Put a complete tune up in it after I bought it. Ran darn near flawless in any temperature until 2 weeks ago. Began hesitating and backfiring. I looked at the engine in the dark a few nights ago and noticed the coil arcing. I bought a "Drive Works" ignition coil from Avanced Auto and installed it. The car seem to run better for a day or so before reverting back to lagging and backfiring. Looked at the engine again in the dark and noticed the coil was still arcing. Took it back and bought an Accel ignition coil. Installed it this morning and the car ran badly from the start. Just looked at the engine a few hours ago in the dark and it was lighting up like a Christmas tree. Purple/bluish light everywhere. Coil was arcing, wires were arcing with each other, the coil to distributor wire was arcing out almost it's entire length against the air cleaner. Car still runs, at idle it will miss and at higher RPM's while driving is "pops" (backfires). I checked the distributor cap and rotor, they didn't look bad. There is only around 15,000 miles on all the tune up parts. Could be a bad coil ground, but I'm not sure how this coil grounds. I believe it's through the bracket? The only wires on the coil itself are the coil to distributor plug wire and 2 wires that plug into the coil itself. I know the newer coil runs hotter so what are the chances another complete tune up with better quality wires solves this problem? Thank you!

when the spark arcs outside the system means it is easier to jump to ground outside that it is to jump the gap at the spark plug. That's not a coil problem (unless the coil is cracked). Look at the wires. Or where ever you see the arcing. Make sure the spark plug gap and the distributor cap to rotor contact is good.

moisture on the wires makes it easier for a bad wire to jump around using the water as a connection to ground. the coil seems to be working great. that why you get it arcing all over.