Extremely long file load times

I'm experiencing extremely slow load times on 'file' nodes. Doesn't seem to vary with the type of file (pdf, doc, xls, etc...).

This actually starts with the upload. The sending page basically seems to be willing to sit incomplete forever. However, when I give up and click on another link - whatever page I select appears (in reasonable time) and displays the node creation message from the upload.

When I attempt to view the new node it will take in excess of 4 minutes to load. It does eventually load and display as I expect, but my users will never tolerate this behavior.

I looked at the apache logs and didn't see anything useful. Caching was initially disabled. I enabled it and saw no change in load times.

I've also noticed another 'new' problem that may or may not be related. I'm now getting the infamous "HTTP request status Fails" message. Changing allow_url_fopen to On in php.ini had no effect.

This site has been running fine for several months...