EGR situation

[trilateral1]

I'm getting a 71 code on my 94 22re. I have checked and rechecked the egr system. Found carbon in lower port of egr and the rubber line coming from it. Cleaned out, checked all others and replaced most as a matter of course. Still getting error. Upon doing vaccuum checks, when applying vaccuum to the egr, which is confirmed to be operating along with thermal switching valve, the engine will make a slightly different sound but doesn't change state in any way as far as RPM is concerned. My question is this, has anyone ever heard of or experienced the intake manifold ports being plugged with carbon internally. I looked inside with a borescope but I can't see any passages. I'm not familiar with this intake so I'm not sure what the layout design looks like in there. This is the last place it could be blocked but seems a bit unusual, but like I said, I have never had one of these on the bench so I am not familiar with it. Thanks.

[trilateral1]

Just wanted to pass this on in case anyone else runs in to it. It was indeed the egr passages within the intake manifold. Everything was working properly but the gasses had no where to go, there was no exhaust gas flow. I removed the exhaust gas temp sensor and used compressed air to force the passages open. The sticky goo risiding in the intake could be heard breaking loose and then it flowed freely. I haven't got the check engine light since this step. Yes, the intake still needs to be cleaned out however.