MOST Windstars were built using the 3.8L engine......the 3.0L being in the minority (like 6%).
Removing the vaccum line from the top of the EGR valve is a very good test to eliminate the EGR system from the list of possible failures.
You unplug it from the EGR valve and plug it (the vaccum hose).
This will disable the EGR system.
NOTE that this should light the Check Engine Light as the EGR flow sensor (DPFE) will not measure any EGR flow.
The EGR valve VERY rarely fails on the Windstar, the DPFE and EGR ports are the most common cause of EGR issues.
Also note that it is normal for there to be a slight vaccum on the vaccum line to the EGR valve whenever the engine is running,.....however it is not enough to open the EGR valve.
The computer (PCM) determines how much EGR flow it "wants" and sends a signal to the EGR vaccum solenoid to open it and create vaccum in the EGR vaccum line to open the EGR valve.
The PCM uses the signal from the DPFE to know how much flow there is and will control the EGR valve to get the signal that it wants from the DPFE.
If you were to plot a graph of the vaccum inside the vaccum line to the EGR valve, you would see a series of pulses.....
NOTE that the EGR system is supposed to NOT operate when the vehicle is NOT moving.
IF the DPFE is sending a "weak" signal.....then the computer will call for too much EGR flow, causing the engine to run poorly.
If the PCM determines that the DPFE is bad, then it will ignore the DPFE signal and disable the EGR system.
I wish that I had the "correct" answer to your problem.
However, I have never had that problem and can only guess.
I would LOVE for it to be a inexpensive fix.
Also, YES, it is common for folks to post a question and then not post back when they solve their problem.
I have asked folks to post back, but they still often do not.
The Camshaft Sensor Syncro,.....if it has not been messed with (removed) or failed solid (not common) then is "should" still be fine.
it is a shaft with a gear on the end that is driven from the camshaft system.
If the shaft is not spinning, you should get a Check Engine Light (CEL) and a code that indicates a problem with the Camshaft Position Sensor signal.
The common issues with the Syncro are a squeeling sound due to lack of lubrication to a bearing on it and the syncro being in the wrong position......which would require one to move it....I have not read any posts about the syncro jumping a gear (there is not enough slop in the system for that).
The Camshaft SENSOR has been known to fail.....the plastic body seams to crack...often near the electrical connector part of it.
The many heat cycles that it gets....sitting on top of the motor.
The camshaft syncro is all that is left of the distributor that used to be on motors years ago.
Now it only serves to tell the computer the position of the camshafts and that signal is used by the computer to "time" the spurts of fuel from the fuel injectors, and other engine functions.
The crankshaft position sensor......I can understand you having problems seeing it.
I have no pictures posted of it....even though I tried several times to get a good picture of it.
Like the camshaft postion sensor, it is a magnetic pickup type of sensor.
For a very rough idea of how they work.....look at your wheel speed sensors.
There is a "exciter" ring and a little block with wires going to it.
Inside the block with wires is a magnet coil that generates a elecrical "pulse" each time a tooth of the "exciter" ring passes by.
Counting how many pulses there are in a given time tells the computer how fast the wheel is spinning.
In the case of the camshaft position sensor it is WHEN the pulse happens in relationship to other events, like the pulse from the crankshaft position sensor, that the computer is looking for.