Yeah, I cleaned the horizontal passages ( one about a foot long under the rear "Y" plenum, and the two little nostrils inside the junction) till they were spotless, but untill I took the intake off and removed that bottom plug, I was never able to get rid of that code.
If you don't want to take the intake off and remove that plug, remove just the back plug, spray B-12 in there, and then push a stiff piece of wire in there. Push it all the way in and then cut the wire off so that about 3" sticks out the back. Form that 3" into the shape of a crank and turn away. The rotating wire will rub against the inside of the passageway loosening up the crud.
In conjunction with this, I extended the nozzle on the B-12 so that I could reach the nostrils through the throttle body. You can hold the throttle body open with a pair of needle nose vise grips. After I let the B-12 soak for a while, I took a bent piece of brake tubing and pushed it in and out of each nostril. Eventually I was able to get some of the B-12 to soak down and loosen up the crud in the little 1" long verticle portion of the passage way.
It was a long process.
Tom
