Took off the coil and boot assembly to tighten a loose plug. The boots came off fairly easily. As I was placing the assembly back on the plugs I noticed about a 1 inch long piece of boot material still wrapped around the top of one of the other plugs. It wasn't a torn portion of the boot, it's a separate piece of black rubber that is tapered at the top and has a bit of a flange at the bottom; sort of like a bell. (Sorry, didn’t think of taking a picture.) I figured that it just slid out of the inside of the boot when I pulled off the assembly. But when I pulled it off the plug and tried to push it back into the boot, it wouldn’t go. Its outside diameter is about the same as the boot’s. When I looked inside the boot for that plug, it looked exactly the same as the other 3. As if nothing was missing. It really bewildered me as to where that piece came from, or what it’s for; but since I couldn’t stuff it back into the boot, I just reinstalled the assembly back on top of the plugs without it. The engine ran fine on the drive to work this morning, but I’m still wondering if I should have spent more time trying to figure out where this piece goes and how necessary a part it is. It's a 2011 1.4L.
I’d greatly appreciate any insight to my concern.