Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 17577)
+++ wp-includes/functions.php	(working copy)
@@ -4255,6 +4255,7 @@
 
 /**
  * Permanently deletes posts, pages, attachments, and comments which have been in the trash for EMPTY_TRASH_DAYS.
+ * Also removes auto-drafts which are more than 7 days old
  *
  * @since 2.9.0
  */
@@ -4296,6 +4297,11 @@
 			wp_delete_comment($comment_id);
 		}
 	}
+	
+	// Cleanup old auto-drafts
+	$old_posts = $wpdb->get_col( "SELECT ID FROM $wpdb->posts WHERE post_status = 'auto-draft' AND DATE_SUB( NOW(), INTERVAL 7 DAY ) > post_date" );
+	foreach ( (array) $old_posts as $delete )
+		wp_delete_post( $delete, true ); // Force delete
 }
 
 /**
Index: wp-admin/includes/post.php
===================================================================
--- wp-admin/includes/post.php	(revision 17577)
+++ wp-admin/includes/post.php	(working copy)
@@ -397,10 +397,6 @@
 		$post_excerpt = esc_html( stripslashes( $_REQUEST['excerpt'] ));
 
 	if ( $create_in_db ) {
-		// Cleanup old auto-drafts more than 7 days old
-		$old_posts = $wpdb->get_col( "SELECT ID FROM $wpdb->posts WHERE post_status = 'auto-draft' AND DATE_SUB( NOW(), INTERVAL 7 DAY ) > post_date" );
-		foreach ( (array) $old_posts as $delete )
-			wp_delete_post( $delete, true ); // Force delete
 		$post_id = wp_insert_post( array( 'post_title' => __( 'Auto Draft' ), 'post_type' => $post_type, 'post_status' => 'auto-draft' ) );
 		$post = get_post( $post_id );
 		if ( current_theme_supports( 'post-formats' ) && post_type_supports( $post->post_type, 'post-formats' ) && get_option( 'default_post_format' ) )