Spark plug tubes are easy to do just pull the coil, sparkplug, and most people on this site use a Transom plug to pull the tubes out,
I just use a simple bolt a couple of washers, and a couple of nuts.
JUst make sure bolt is long enough and washer is small enough to fit in hole..
Drop the bolt in until the washer goes past the last part of the lip on the tube...
Use a screwdriver and pry the tube out by placing tip under the washer as shown
This tool allows for more force to be used to remove the tube and less breakage than using the transom plug idea.
I was asking about the smell out of the vents if it was sweet as this is a indicator that the heater core is leaking...