hi I am having the same problem with F8 not working.
I purchased GTA5 on steam last night and downloaded the menyoo files and followed the instructions. I have have never had mods before so don't know if I have done it right or if there's something simple I need to do to get it working.
I haven't attempted any other mods as of yet until I get Menyoo sorted.
I would appreciate any feedback
regards Jonny