Ok so when I start my truck it idles great for about 5 minutes then a vaccum leak develops and it idles really rough as if it had a cam in it. Then after about 5 minutes of that the vaccum leak stops and the idle is smooth as silk again. Also when I drive the vaccum leak starts and the A/C stops blowing cold. Then as soon as the leak stops the A/C works properly again. I have no clue where to start on this one. Anybody got any suggestions where to start looking?