So my 03 6i has been having problems the past month, at a stop, the engine has a shutter to it. It acts like its going to stall and the RPMs drop to 250 and then it bounces back up and just idles roughly. This past weekend I finally put the time in an removed my intake manifold and replaced my pc hose/valve (which was cracked pretty badly). I also replaced all the vacuum hoses I could see as I put it back together. Unfortunately, the problem is still there and it is still throwing the same CEL codes, P2187 p0443 p2177 p0441. Is there anyone than can direct me to the next possible solution?