about miss at idle or low speed on 2001 3.8L windstar

Just want to share my experience with this problems submitted a few days ago. For me, same van 2001 with 3.8 and exactly the same problems, very light hesitation at idle since a few weeks. The van has close to 200km and the coil pack has been replaced about 3 years ago because of 2 cylinders misfire. The spark plug has also been replaced 30 km ago ( Autolite dbl platinum) so not very old, and ignition wire too (june 2007)
I have used my old timing light to find that one cylinder at the front was not blinking regularly and even when I rev the engine I can see that the blinking was not always regular. So according to that ( and because I had a long drive to do) I have bought a new coil pack and after having installed it, I have seen that unfortunatly the problem was still there (like one of you I think)
So I did my trip and after I have continue to investigate. The spark plugs and the ignition wire were not old so I start suspecting an injector but how come an injector could make a missfire coming from the coil? At this point I have disconnected the injector (electrical connector) of the missing cylinder thinking that may me the ECM would make that the coil to stop sending spark to the spark plug ( because the injector was not working) but nothing of that happened and the timing light have continue to blink ( irrigularly) no mater if the injector was connected or not. I was just hopping that the ECM was not defect.
Following that I have decided to remove the spark plug of the missing cylinder and guess what, this damn spark plug ( of just 30km old ) was full of hard ash, leaving a gap of less than 0.010mm which was the culprit of this light misfire. I have realized that my old 3.8 engine has a little problem with the stem valve seals and some oil has contaminated the spark plug. I have temporarly install an old plug and no more misfire or hesitation and the timing light is showing a regular spark. Anyway I will install new plugs but have also to plan a valve seal job. If I would have know, I would have certainly start by removing this spark plug in first but anyway, now I know.
Hope this maybe will help some people in the future.

Thanks for the info.. I use to check my spark plugs regularly on all 4 cyl. cars I had. I can inspect the front of the Windstars with no problem but seeing if i don't want to go to the trouble on removing the back ones I don't bother inspecting them.. I can now remove the back ones ok.But its still a pain. Yes checking the spark plugs is a good way to find out whats going on..

Ash forming on the spark plug may not mean oil could be leaking by..If you use a strong fuel cleaning treatment can cause this as well.. I would inspect some of the front spark plugs as well to see what they look like.. All though one of the signs of ash on the spark plug could be caused by the valve seals I normally look for black coating on the spark plug before i think of getting a valve job done.. If you ever go the valve job route.. Have a machine shop port and polish the heads.. If you do the work your self as far pulling the heads. I normally let the machine shop replace them for me.. I think the last time it was 200.00 for the port polish and new valves, guides,seats and seals. On a single cam 4 cyl. So may be around 300.00 bucks or so for the v 6 i would assume.

you know ,its intresting , I pulled the spark plugs on my suspected cylinders and they looked normal........this is schadd 1971 and I wrote recently and a miss as well.....mine has gotten somewhat better.....still there a little bit...still suspect the injector.....unless someone suspects something else

were both of yours have deposits or just the one........