Re: Iran threatens to block Strait of Hormuz in case Iranian oil faces sanctions..
In 1990, Pakistan sent troops to Saudi Arabia to guard Medina and Mecca when the first Gulf War was about to break out, though those two cities were obviously not in danger from Iraq. However, the Saudis asked for it as a means of freeing their forces from the area and as a means of having Pakistan show solidarity with them.
Saudi Arabia has a great deal of influence over Pakistan that cannot be discounted.