I'm working on Genie Model Z60/34; Serial number z6006-6321. When I start machine and put it in drive it runs perfect in Forward, reverse, and right turns. But when I push the joystick left, sometimes the steer turns left, and sometimes it doesn't. I did notice that when I tap the joystick to th left it will turn. So I replaced the joystick and it still has the same problem. Please help.