I have some web pages written with PHP/mySQL, but they are running much slower than usual. Is there any way to debug and find out which part is the reason? All are hand code, not from any CMS.
Can you post our code? We may be able to identify where your queries/code can be optimized.
You could try installing xdebug and checking the results in using cachegrind or webgrind (more info here: http://devzone.zend.com/article/3829)