electrical arcing from timing cover to crankshaft pulley when running.Any ideas? on 2006 Kia Rio

occurs whenever vehicle is started and running at idle.
as crank is turning, there is an intermittant arc that goes from timing cover to the crankshaft after the vehicle is at operating temp. I hve never seen this before.

2 answers
poss loose grd cables and not making good contact
Bolt holding the plastic timing cover on is hitting/rubbing the crank pulley! Creating sparks.
That's my guess.