Is Drupal's cron.php being hit every hour? If yes, my guess is that it's related to an errant Drupal module. You can try isolating this by grepping for hook_cro

Is Drupal's cron.php being hit every hour? If yes, my guess is that it's related to an errant Drupal module. You can try isolating this by grepping for hook_cron in your contrib folder. When you have a list of likely culprits, you can check their corresponding issue queues on Drupal.org or just dig into the code. Either way, it's likely a bad Apache configuration. Try posting in the Drupal.org support forums. You're likely to get the help you need without being charged for it. The Drupal community likes to help its own, so I suggest posting in the Chicago group at groups.drupal.org/chicago, too.