even more interesting than I thought!

M-W has this:

Main Entry: 1coil
Pronunciation: 'koi(&)l
Function: noun
Etymology: origin unknown
1 : TURMOIL
2 : TROUBLE; also : everyday cares and worries <when we have shuffled off this mortal coil -- Shakespeare>


http://www.m-w.com/cgi-bin/dictionary?va=coil



formerly known as etaoin...