Just started the car for the first time this year. Lots of crackle or sparking noise from engine bay. Sounds like arcing. Can it be from moisture from sitting all winter? Never experienced this before. No visible sparking by the way. Car also runs great. No stumble, so I don't think it's a bad wire.

 

I'd start the car in complete darkness and look around. Friend of mine had a plug wire arcing on #6 and that's how we found it.

 

I would check it out a little closer, so that you don't have any smoking surprises! You could have had varmints chewing on the wiring while it was put away.

 

My air conditioning compressor makes this same noise... I have no idea why, it works fine.
Turn your A/C on and off and see if the sound stops.

 

My AC is dead, has been for awhile. Checked again, same noises, but it was not dark enough