PHP pre-processes before sending to the website, so if you were to put a sleep method, it would only delay the page frrom displaying for that long.
The -easiest- way will be to use jQuery for an ajax call, then use setTimeout to echo text every 5 seconds:
// Assuming jQuery is linked
$(function() {
// Connect to the php file
$.ajax({
url: 'php-file-with-tfcari-var.php',
type: 'POST',
success: function(data) {
// data is what the ajax call returns, let's assume it's the $_POST variable from php
var tfcari = data.tfcari;
// Now you can loop every 5 seconds with a self calling setTimeout method
var poll = (setTimeout(function() {
window.document.write(tfcari);
}, 5000)();
}
});
});