I am removing the intake manifold due to severe dirtyness and a unfindable oil leak. I have the exhaust manifolds off. I'm probably gonna do the head gasket too. should I do the chain as well? I cant get the intake man off easily. its loose but wont come apart from the head. I have all the bolts off and the one nut in the center by the cold start injector I think it is. the brace underneath is also off.