genie z45/25

we have a genie z45/25 starts no problem runs great, in the stowed position I move forward to go and it goes about 4 feet then comes to a complete stop. I have to shut it off then start it and I can do another 4 foot. same if in revers. I got the code which it 5-4 I looked it up and its a drive valve. anyone have any ideas?

genie z45/25