i have hostmonster and at certain times i`ve noticed my site to so slow it won`t load.and a hour later it works.Any ideas?

possibly they overselling the server or the bandwidth and the slow times are when other sites are hogging the resources.
There are 1,161 sites located on the same IP as your sites.

Are these "certain times" regular or fairly random?
Do all three (in your sig) "slow down" at the same time?
Is it only your sites or are other sites slow at the same time?

possibly they overselling the server or the bandwidth

They most certainly are overselling the bandwidth, but the issue would be the overloading. The two are not synonymous.

andrewp730, when that happens, try a quick check with host-tracker.com, and see if the same slowness is present in other parts of the world. It can always be a routing/ISP issue.

That might be cronjob on your neighbor script and as result overloading as Dan said.

Try find a pattern to the slow load times. Always 5 minutes after the hour? Always at noon?

After you discover the pattern, notifty your provider that your server is always really slow at X time. Maybe they can disover if it's a single user that is hurting everybody else.

Usually if one or 2 customers are dominating a shared server they'll warn them to tone it down, or simply terminate their usage.