My garage door opener has developed a peculiar problem. When opening it only rises about 3 feet then stops. If I give it a push it will open all the way. Then when I go to close it it runs about 3 seconds then reverses itself and stops. After stopping there is a relay clicking noise that also makes the light bulb flash. If I disconnect the door from the track the opener functions normally and the door opens and closes manually without any hint of binding. I did find some loose mounting bolts for the rollers and after tightening the problem remains with the door attached to the opener assembly. Its not a sensor problem that I can tell since the green LEDS are both lite on each one and turn off when one or the other sensor is blocked.