2005 Chevy Impala ignition

[carriedi]

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.