Wow, that's a lot to reply to.
No codes have ever been set with this problem. I may pull the vac hose to the EGR to see what comes up in the codes.
Both the APP 105 and 765 plugs are listed for the '99 3.8L Windstar. The 105's appear to have a longer threaded section than the 765's now in the engine. One fellow who had this problem told me he got rid of it by switching to the 105's. Some say it is good and some say it is bad. These plugs (the 765's) worked perfectly for almost 25,000 miles, it is only the past 5,000 miles or so that I have had this problem.
Alternator was new last year.
I have a code scanner so I never clear CEL's by disconnecting the battery.
Problem happens in 3rd or 4th gear, low RPM's, usually while trying to climb a hill or slight grade under low acceleration. If you tip into it the miss never happens. It has been getting steadily worse in the past month and seems to be more prominent on damp days.
To repeat what I have done so far:
-new coil
-new wires
-new DPFE,
-cleaned MAF
-checked plugs
-checked DPFE function
-looked for obvious vacuum leaks
-IMRC links are connected and both IMRC's seem to be functioning as best I can see
Thanks, All