Mamiya RZ Pro II wont reliable fire shutter

My RZ has developed a problem where it wont fully fire the shutter. The mirror will flip up and the shutter will shut allowing the aperture to get to its proper size but then it doesnt re open allowing the light to hit the film. I removed the front plastic cover from the mount and if I slightly apply pressure to the gear at the bottom responsible for moving the bayonets it will then finish the way its supposed too. Its also random sometimes it works perfectly 10 times sometimes I cant get it to fire properly 10 times. Do the gears need to be lubed or is there a spring that needs to be tightened. I tested it with two different lenses to make sure it wasnt the lens.

Not sure if there if anyone else has had this issue but I thought Id ask.

I can provide a video if it is helpful.