server hanging on php site

Hello, I'm running PHP 4.3.1 on Apache 2.0.48 (on Slackware). I've been having an issue where accessing a certain PHP page causes the whole httpd to stop responding momentarily; no sites will load, those that are loading stop in the middle. But after say 30-45 seconds it continues just fine. I don't see any errors or an increased cpu/memory load. It isn't always on this specific page (well its a livehelp program) and has done it elsewhere but I forget what I was using. What could be causing this, or how should I diagnose it? Thanks, Bryan