macbook wakes from sleep, restarts when shut down, tried everything. "wake reason = "
My macbook (2008 unibody, 2.4ghz, os x 10.6.8) will not stay asleep, and it restarts when I shut it down. For example, I'll close the lid, it will sleep, then wake a few seconds later, and eventually go back to sleep. After a few cycles of this, the CPU reaches over 80 celcius, but nothing indicative of heavy cpu usage in the activity monitor except for "kernel task." I guess this is because the fans have to keep shutting off when lid is closed. Of the things I've tried, the following have not worked:
*fiddling with all possible energy saver preferences
*disk utility repairs, even with the snow leopard install disc
*resetting pram and smc
*loading into windows 7 partition, same thing happens
*loading into my external HD, same thing happens
*deleted everything in the LaunchDaemons folder
*turned off bluetooth entirely
*turned off airport
*turned off "Set date and time automatically"
*nothing plugged into USB
*tried with/without magsafe plug, with/without battery, same problems occur
*no errors returned with applecare's Techtool Deluxe
*ran every maintenance script I could: crons, clear cache, rebuilds, updates
*ran the hardware test from one of the install disks, no problems detected
*turned off login items
I've studied the messages in Console.app like my life depended on it and the only thing that's bugging me is that I get "kernel---------Wake Reason = ". It doesn't give me a wake reason, it's just empty. I can't find anything around the net that could tell me why this occurs. I put "syslog |grep -i "Wake reason ="" into the terminal.app and apparently this has been happening for a week now, hundreds of instances of no wake reasons.
Could this be a hardware error?
MacBook, Mac OS X (10.6.8)