The EGR valve hasn't been blocked longer than a week, I will open it up this weekend. As far as the seafoam treatment, I did that when I did the major tune up, that was about 800miles or so ago! It smoked a lot but didn't really improve things. It will get another one on the next oil change just to make sure everything is out! I will be doing a compression test and checking the temp of the cylinders this weekend just to make sure all the cylinders are up to specs.