i think i have the same problem
nothing from the Z axis ....
My cougar is 1.5 years Old BUT NEVER been in USED.
Mybe for 5 min in the day i bought it.
it was so stiff so i returned to my CH set and stored in the cupboard.
in my second try after couple of month i remember doing that
firmware update ... thrrotle didnt responde after.
i told myself i will check it later .... and stored it again.
your post on this issue make me wonder again ..
so i checked my Cougar today.
same symptom !
what i have to do now?
what a bad luck ......
my CH stick going to die soon after 9 Years of great service,
and i need My Cougar to be operational ...