Cleaning lower & upper intake manifolds

Hello, I have been reading all I can about the upper & lower intake manifolds because I have been getting water in the cylinders on my 1998 3.8L engine. I have come to the conclusion that my problem is the lower intake manifold gaskets, and I have taken apart my engine to that part.
My question is what is the best method to clean the upper & lower intake manifolds, and the engine section below the lower manifold?

Also there is a fair amount of gunk around the holes that the fuel injectors went into. I would like to clean them, but I am afraid of the gunk getting down into the cylinders. Any advice in technique and cleaning agents to use would be helpful!

Thanks
Guy:rolleyes:
1998 Windstar
3.8L engine

You have a good and healthy concern for getting things down into the combustion chamber ... not good! Chemical cleaners would scare me.

I would only suggest rigging up a small dia rigid suction tube/scraper and adapting it to your ShopVac. The idea would be to scrape gunk with this thing while it's sucking away. You could further go around the engine, rotating the crank ... closing both valves on the cylinder you are currently working on ... this way nothing (solid) can get away from you and fall into the combustion chamber. Pull the plugs to make the crank turn easier.

Happy cleaning!