mifire on #5

2000 windstar 3.8l . recent tune up. idles better now but runs rough when in gear and accelerating has poor respone. diagnostic say mifire on #5. how do i correct this? what all should i check? fixin ford daily

You may have a bad coil. Try reading the 3 pages of the post "Bad coil pack symptoms" four posts below yours.

The coil is hard to get out without taking the cowling off over it. That's the plastic and metal pieces that go from fender to fender and contain the wiper motor and mechanism. The plastic is held on with 4 or 5 plastic screws and then snaps off with some 1 inch square fasteners along the windsheild. The metal with wiper assembly is held on by around a dozen metal screws. If the metal screws have rusted threads try wire brushing them from underneath, spray with wd-40 or something and carefully work them out and in brushing rust off as you go. That's what I had to do with my 2001 model that lived in Mn before I bought it. With good screws it only takes 15 minuites to remove the wiper arms and remove the cowling.

The coil can be removed & installed with the cowling on but you really have to know where the wires go back on by feel. Either way draw a diagram and mark them with tape or something.

Good folks here will have some other ideas for you too.

Cylinder #5 is on the front bank.....middle cylinder.
EGR ports usually cause misfire on #3 and/or #4.....
One thing that I recommend you try......easiest and cheapest.....get a can of Berryman's B-12 Chemtool and add to your next fillup of gasoline.
This has cleaned my fuel injectors when other cleaners have failed to correct the issue.
I have been down this road several times.......and the Berryman's has solved it each time.
If it does not solve it.....it is good maintenance anyhow......and you are only out $3-$4 and little effort.

I suspect the coil pack because I had the exact same thing and it was the coil pack....it gets a lot of heat and gets a hair line crack , so I have been told ... but I replaced the ciol and bingo!!!!!