Slow load time of WordPress 3.9

Hello,

I’ve setuped a website for my best friend, and since a few weeks, I’ve noticed that the load time of the website went from about a second to 3 or 4 seconds.

After digging a bit on that, and deactivated all the plugins, I’ve noticed that the problem is located on the wp-settings.php file, in the “do_action( ‘init’ );” part.

I can’t figure out why this action is taking about 1 second sometime.

Worst, I’ve done some tests by calling this file in command line and the execution of wp-load.php file can take up to 1.9 second. But on the same server and without doing anything, it can take 0.5 second.

Any help, any clue would be much appreciated here, because my friend is loosing trafic because of the bad response time.