That sucks. My Regal did what you describe. I ran it at night and misted the coils with water. You could see the arc. Luckily my coils were up front and easy to get to. I think it took longer to find the tools than it did to change the bad one.
They are easy to replace. I just don't want to spend more money on parts until I'm more confident I need them. I can buy them locally right now for about $100 or I can wait a few days and get them off ebay for around $40.