miss at idle or low speed on 2001 3.8L windstar

hi, I have a 2001 windstar 3.8L and is keep in tip top shape...I tune it up regularly, change filters , even did the valve cover and intake repair and replaced the intake cover that separated ..... lately Ive noticed a misfire when idling or going slow ....quite noticable...... wonder where to start checking........could it be ignition (like a coil pack) ? it idle smooth other than the miss,, feels like small jerks.....accelorates and runs high way speed fine..i think,,,will check for sure tomarrow,,,,any ideas????

I have an update on my problem...code PO 305 came up......cylinders 5 misfire detected....wires seem ok ..could it be the coil pack ?

It could be the coil pack....these seem to fail on the newer windstars......
The other thing it could be is dirty fuel injectors.......having tried MANY cleaners......I have had the best success with Berryman's B-12 Chemtool, in the metal can.
It is also one of the less expensive cleaners on the wall of many cleaners at the auto part stores.

A spark plug wire can also cause this.

I had an idea and took a timing light and put it on the wires and guess what?...you could see the miss , a gap or an irregular blinking in the light....that has to mean the coil, right ....it seem two wires showed that miss.........

The data for my '96 shows that the coil pack....which contains 3 coils has cylinders #5 and #1 sharing coil 1

Coil 1 has Cylinders #5 and #1

Coil 2 has Cylinders #3 and #4

Coil 3 has Cylinders #2 and #6

With the coil pack plug wire side up.....and the input wire harness on your right......the coil at the top....farthest from you....is #1,
#3 in in the middle
#2 is closest to you

So.....if the other wire that did not have spark was cylinder #1.....back bank of cylinders......driver's side.....then it would indicate that coil #1 is not delivering current through either wire.

The timing light flashes to indicate that the wire that you have clamped onto has had a pulse of CURRENT flow through it.
So......missing flashes.......means missing current pulses.

Lot of words....but trying to have the response give the theory......and also help to others who my have similar symptom.......missing spark on 2 cylinders.....but maybe a different 2.

A loose connection to the INPUT side of the coil pack could cause this.....but the trend seems to be the coil in most people's posts.
Upon removal of the coil.....you may or may not be able to see something wrong (crack....etc) or you may not be able to see.

I was really convinced that it was the coil because I had a similar experience with coils before so i bought a coil and tried it and not an difference..... i couldnt believe it....in fact my wife sayed that the miss cleared up that day before I tried the coil...I still feel it a little when I rev it and it comes back down....you hear it slightly as it returns to idle...a small miss or two.. has not triggered the check engine light...idles smooth,,pulls ok....think maybe an injector,,,,????? how about a injector/intake cleaner job that many places offer.....any other ideas/ areas I need to check.......by the way is there a way to check/test a coil?

bad plug wires........or dirty fuel injector are suspect.
I have chased my tail more than once with a dirty fuel injector.
They seem to build up some crud inside the "end cap" over the spray end of the injector.
This is outside of the injector body......
The ONLY cleaner that I have found that works is Berryman's B-12 Chemtool.
I would give this a try.....might take a while for this to clean them out.

Also....don't forget routine service items like fuel filter (a clogged fuel filter puts a additional work load on the fuel pump) and spark plugs.
The original spark plugs are good for 100K miles.....
Those spark plug wires are now 7 years old......

could catvents be right.....I pulled my plugs and they looked normal no deposits.....have 105,000 on my 3.8L........have you read catvents,wiswind

It is possible for a spark plug to be defective and cause the problem....
As your plugs are clean......it makes it a less likely cause...but still possible.
Also.....and more likely, unless you have already changed them, would be the spark plug wire(s).

As far as the fuel injector......they are quite reliable......except for the need for the cleaning.
Dirty fuel injector(s) have caused me the issue with a miss a number of times.

Fuel filter and fuel pressure are also possible causes......the windstar does NOT monitor fuel pressure or flow.
Some have had intermittently low fuel pressure cause strange problems.
Keeping up on the fuel filter is a good idea for this.

After performing the isolator bolt/intake fix, I noticed the van was using more oil than before the fix. To go along with the intake fix, all plugs and wires were also changed at that time. A short while later, a miss developed in #5. I changed the spark plug and the miss went away for about three months but returned. I suspect some oil fouling as the plug(s) were slightly discolored. I believe the cause of this is the PCV system sucking too much oil. This is just seems to be another quirky design issue with these 3.8L motors.


2001 3.8L Windstar

What type of sparks plugs are you running? The double platinums are the way to go, people seem to prefer the autolites though 12 ounce recommends champions, I believe he specifies the type in his engine rebuild thread. By changing the coil pack you probably saved yourself some grief later on anyway. Did you clean the egr ports when you did the intake repair? Have read that clogged ports will lead to a misfire. Also take a look under the hood in the dark to see if any arcing from the plug wires is present.

it was The coil after all.....van is fine now...