why is my Track Pad jumpy?
Errotic and Jumpy trackpad
Somehow my trackpad become jumpy.I've tried to clean the trackpad and my hand. But it stilll happen. it only happen when my Mac is connected to the internet. but not always when my my Mac is connected it happen (got it?). I've asked the apple store, but they dind't know why either.
Take out the battery, flip the machine over and check the ribbon cable that runs from the trackpad to the keyboard, to the connector. Known issues are: loose at connection point, or ribbon could be wrinkled, lose, crimped so that pressing keys moves the connector.
Some people have had luck just pressing it flat against the keyboard,(especially where it passes through the slot in the sidewall) other have shimmed the cable using a folded sticky note beween the cable and the battery.