This problem is not the wake from sleep or one of the screen lines/glitches problem.
My G4 667 will force itself into sleep, or just crash [hard crash/black screen] whenever it is moved, bumped, typed on, or looked at funny. It does okay when external keybd/mouse are plugged in, otherwise it's VERY sensitive. It sometimes will wake from it's sleep, and sometimes will make bad static noises, then crash. It's definitely hardware. There was an apple discussion 'narcoleptic titaniums' in which many others had identical problems, that discussion seems to have been removed from apple support?
In that discussion one person claimed a successful repair only when he had the 'rib frame' replaced, most people had logic boards and everything else replaced with no success.
Another person suggested it may be a pinched cable by the space bar.
IF ANYONE has or knows anyone or any repair center who had this problem or had any succes dealing with it, pleeease let me know. Powerbook medic won't even take it, and apple has been unable to repair it 3 times.