Unless you think you have a leak or some other problem, forget the intake manifold. The exhaust port plugs up because of carbon accumulation, intakes do not have this problem. Just pull the exhaust and look toward the piston, if the port needs cleaning, it is easier to pull the cylinder. If you are careful, you can scrape most of the carbon with the piston over the port, then finish with the piston down. If you can hanh the ped with the exhaust port pointed down it would help.