I have a 01 Mazda Tribute, and I'm trying to change the back spark plugs which are covered by the Manifold, I think that's the name of the large platting covering the back plugs. In able to remove the back plugs, the manifold, needs to be removed to obtain access to the rear plugs, and to be able to remove the manifold you have to remove 3 hoses located on the back of the manifold. I would like to know if it's OK to remove these hoses?