Okay, I went ahead and pulled the upper intake off and found my P0401 problem, I think. The little channel where the egr gas goes back into the manifold was completely gunked up with carbon deposits. I went ahead and had the upper intake dunked to clean it all out. Broke one of the vacuum lines going into the intake though.
Also, going to go ahead and replace the egr valve anyway.
Should I go ahead and go further and take the lower intake off? It's got some pretty bad carbon buildup on it also.
Thanks
