I noticed that many online stores sell so called ignition coil boot kit with spring and resistor:
More Information for BECK/ARNLEY 1751058
It will be very nice to know if someone fixed misfires by replacing boot/ spring with resistor instead of changing entire coil.
Based on the diagram a coil has built in fly back diode with voltage regulator (?)
but I am not sure if these parts are failing. (07 Camry V-6 has defective coil issue addressed by TSB and it is caused by failing IC inside of the 4 -wire coil; our Fits having 3-wire coils).
I am seeking an opportunity to get bad or marginal coil and run it on scope or attaching a megger to it!

 

It is the coil pack boot that generally fails. I changed all four boots to troubleshoot an issue in my car. That didn't end up being the problem, but the replacements worked fine for while I used them. Some folks have complained that the generic boots or cheap coil packs (sub $70 ebay sets of 4) don't last long.

 

Had the intermittent jerking at idle a/c on. Ordered all four coil packs on Ebay for $44.00 shipping was included. Checked them out when received and seems like good quality. Removed old coils (had 70,000 mi. on them) and pulled apart at the boot and top coil found a lot of corrosion in there. Put the new ones in and MAN does this little car scream now. Did not realize how much power I had lost due to it happened slowly over time.
My suggestion at this price is to replace all four and you will not be sorry, believe me I am one happy camper. By the way, the jerking is totally gone!

 

The OEM Hitachi coilpacks are now less than $50 apiece at rockauto last I checked. I wouldn't trust the other aftermarket brands to last anywhere near as long. Do a search on this forum for details.

 

I just install 4 brand new hitachi coil on my fit this week and wow, the difference its just amazing! I had some missfire trouble before that , the engine just can't take any load. Finally its fun to drive