Just keep turning the nuts as they are stuck on the studs. This will unscrew the studs then the cover assy can be taken off. After the cover assy is off the using a second wrench to hold the stud remove the nut on each stud. If I remember correctly the ignition coil is mounted with regular screw and one of the studs so it will need regapping and the stud tighten to spec.
Blower Housing
Stud 10 N·m (88 in. lb.)
Nut 8 N·m (70 in. lb.)