Ercoupe project flies unstable in pitch and yaw

Hi, I bought Ercoupe 415CD over a year ago. It had not flown in 15 years. I went through and inspected thoroughly for corrosion and freedom of controls(nothing binding or rusted). Had the local mechanics do an annual although they have no ercoupe experience. Did all the AD's and when it was time to fly, I did some high speed taxi's and adjusted nosewheel for straight handling on the ground, The first time I took it off the ground it was way out of rig. We went through the whole rigging procedure and it still is very unstable in both pitch and yaw. I am planning on getting all new heim joints to try to eliminate as much of the play as I can, but can't come up with any reason for it to be so touchy in pitch. Looking for idea's so I can finish this project.