There is 1 EGR port in the lower intake manifold for each cylinder. Cylinder #1 and #4 are the farthest away from the EGR valve, and seem to be the last ones to become clogged. So, when the other ports become clogged, ALL the EGR gasses end up going to 1 or 2 cylinders, causing the "missfire".
Pulling and plugging the hose to the EGR valve will disable the EGR system. Please take note that this will cause the Check Engine Light (CEL) to come on as the computer has sent out a command to open the EGR valve....and is expecting to sense EGR flow.
The EGR valve does NOT open at idle....so you will need to take the car for a drive.
What you are looking for is, "Does the engine still have a miss?". If so, then the problem is most likely something else.
If it does not, then you will want to have the EGR ports cleaned.
I had a missfire on cylinder #4 that was caused by clogged EGR ports at 135K miles.
Then several months later.....I got a slight miss...that I was chasing for another several months until it also lit the CEL....and was a miss fire on Cylinder #1....caused by crud on the end of the fuel injector.
Neither issue is a major repair, but should be repaired.
A link to some pictures from my '96 windstar follows.
http://community.webshots.com/album/201931518cScpNK