Random Misfire, new wires arcing

[94Sierra4x4]

1997 K1500 z71, 5.7L/4l60e

Truck has been running rough on and off lately. Mostly only when running fairly hard up a long hill. Will start losing power then shaking and eventually causes the CEL to flash the random misfire code.. Last week it happened again and didn't go away like it had previously. Now random misfiring at idle and especially in gear with brakes on/applying throttle (under load)

Anyways.
Replaced cap and rotor as they showed signs of wear. No change.
Plug wires were old and arcing out in the dark so I replaced them. No change, new NGK wires still arcing.
Spaced wires out better, still arcing.
Also still throwing same codes and running the same.

New wires faulty?
I pulled one plug out and it was showing perfect signs of where. (The wire to this cylinder was arcing)

What would cause the new wires to arc other than them being faulty? Bad coil? It looks good.. Lol

Thanks guys. Been a while since I've posted. Hope ya can help me out!

 

[94Sierra4x4]

Pulled all drivers side plugs, all look good, cleaned them the bit that I could, snapped the wires back on good.
Same issues.

Distributor?
Coil?
Is it possible for the coil to put out too much voltage, and the resistance is too high @ plugs so it's jumping through the insulation to the other wires/block?
Just spit balling.
Wish I had a spare coil to swap in for s&giggles

 

[meterman]

I say bad wires


Sent from my iPhone using Tapatalk

 

[Tech]

Good wires should never arc.
Plug gap and electrode diameter determine the voltage necessary to jump the gap. Platinum plugs have a nice small electrode dia. They also last considerably longer before they wear out. You can run a larger gap with platinum plugs and not stress your system. Larger gaps generally equal better fuel economy and easier starting/ less flooding.
Buy new plugs and good wires.
gap them.

 

[RyanR]

Interesting but it does sound like junky wires, even if they are new. Check out the $30 Taylor's from Summit. They work great for me. For plugs NGK TR55s. I prefer NGK copper cores in all my engines, work great and cheap... can't beat em in daily drivers or racecars IMO.