In addition to the sticking EGR valve, your hot intlet tube from the EGR valve to intake manifold could be plugged up and need to be reamed out.
Steve Brotherton (stevebfl) has an article posted in the DIY link at the top of the page that illustrates this problem. I think the article is called Evalutating Electronic Engine Controls.
Also, While you may have a bad coil wire, it is more common that the problem is a bad connection between the coil wire and its resistor boot. Change the three boots under the coil wires first.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".