Can't say for sure about the 5A,
Found this on a web site:
"How many amps does a ignition coil draw?
Ignition Coil (single oil-filled coil older vehicle) - 3 to 4 amps."
So 5 does not seem out of line.
but with the coil disconnected from the dist. there shoud be no draw from the coil.
How and where are you taking the amp reading?