i read in this thread that this is only an issue for early model mdx's, but i couldn't resist trying on my 2005 with 115,000 miles. while changing spark plugs, engine oil, air filter, tranny fluid, ps fluid etc, i decided to pull open the manifold and give her a good cleaning too. what i found was similar to earlier posts. no buildup of any sort, but i did see a little black powder, and a mild varnish like coating on all surfaces, in particular by the egr tube. i cleaned it all up with throttle body cleaner, and after firing it up, found a little initial hesitation (likely a "seafoam effect" of getting a little fluid down into the valves), but after a smokey start up, she settled into a nice smooth idle, and then ran fine afterwards. i am not sure that i feel any difference, but it was running strong before all the maintenance. just curious: what are the butterfly valves in the manifold? are they to shorten/extend the intake runner length?