2002 Windstar Rough Idle, Spark Plugs, Coil Pack?

Hi All,

Have an '02 3.8 Windstar that's been running rough at idle ever since it turned cold. The colder, the worse the problem. Starts fine, but after a minute or two of driving, then idling in park or at a stop light, it starts idling really rough and almost stalls. After warm up it runs fine. I am currently replacing the plugs and wires. However, i am suspicious of the coil pack since the number 5 spark plug looked a bit dirtier than the rest and smelled like fuel when i removed it. The tang electrode is dark on one side and has a grayish brown haze on the other size. So my question is, should i be able to tell from my spark plugs if my coil pack is going bad? I am actually in the middle of the job now and would like to know sooner than later so i don't foul up another #5 plug. Thanks y'all!

Best way to tell about plug colours is to go to a website for a manufacturer and look at their stuff. They will show colour pics and you can get a proper diagnosis. I think the grey part means overheating of the plug end, but don't quote me on it. Seems strange that being cold affects the plugs at all? Anyway, can't hurt to have fresh plugs and wires unless you don't use Motorcraft or Autolite plugs. Then you WILL have issues. Maybe not right away, but the plug life will be short, been there done that. Also, make sure you use a proper spark plug socket (rubber lined) so you don't crack the plugs.

Have you had the Check Engine Light (CEL) come one with the rough idling?

Thanks for the insight. So, I replaced the plugs(Autolite Double Plats) and wires last weekend. By the way, did the plugs from underneath. It was a big job (about 4.5 hours) and if i did not have thin forearms, i don't know i'd have been able to do it! I might try removing the cowling if i have to do it again. The van seems to run fine unless you stop and idle after about a mile of driving. It just sounds like it's missing every once in a while. And it's not so much that you can even see the RPM gage drop, but it IS pretty distinct. So, my next question. Since the problem wasn't the plugs and wires, could it be the coil pack? Is there a way to test the coil pack to see if it's good? I still can't reconcile the fact that it doesn't do it after it's hot. Also, no CEL yet... Thanks!

If you can have on hand a timing light you could certainly see if one a the wire would cause a misfire. Soon or later the ignition coil will have to be replace. Unfortunatly you have replace your spark plugs from underneath; if you would have done the job by the top (cowl vent) you would got acces to the coil and see the condition. Cowl pack is a regular issue for the Windstar, mine has been replaced 2 years ago because of engine misfire. It was showing several cracks on it. I would take a look to his physical condition, however misfire can occur even if the coil does not show any visible failure.

So, does the coil pack explain the intermittent nature of the missfire? I.E. it is fine when first started, and fine when it's hot. But, it shows up when you idle at a light (or in park) a mile or so after startup.

So, does the coil pack explain the intermittent nature of the missfire? I.E. it is fine when first started, and fine when it's hot. But, it shows up when you idle at a light (or in park) a mile or so after startup.

My 02 had those exact same symptoms when it was throwing the 171/174 codes. I did the intake manifold isolator bolt routine and have not had those problems since. That was about 5 months ago.

For about the past month however, the van has been idling rough for a few minutes after a warm restart, this time no CEL. I have not found that problem yet.

Have you found your problem yet?
I was having a minor misfiring problem and it came up with cylinder 3 misfire code.
I just got done (hoods still up) changing my plugs and wires and now it's even worse than before I started.
I didn't use autolite or motocraft, but they are platinum plugs, I am wondering now if it is just that I used the wrong plugs.
Any insight?

The multi-prong type of spark plugs have been reported to not do well in the windstar.
Otherwise, the ones you used should be OK, but not last as long....the AutoLite and Motorcraft Double Plat' plugs have the platinumn on BOTH the center and "ground" tab.

A misfire on cylinder #3 can also be caused by clogged EGR ports.
The ports normally clog from the driver's side, closest to the EGR valve, first.
This leaves #3 and #4 as the last ports open, and the excess EGR flow to these cylinders can cause a misfire.

Also, misfire can be caused by dirty fuel injectors.
I have found that Berryman's B-12 Chemtool, in the metal can, cleans these up......where MANY other brands that I have tried do not.

Wow, Thanks that was fast. You said to try that chemtool, is that for the fuel injector or the EGR valve?
Also, why do you think that it would have gotten worse after I changed the plugs and wires... I keep lookin but can't find anything. I know their ran right and seated good. I don't get it.
Thanks agian.

Did you use a rubber lined spark plug socket or just a socket? I cracked a plug using a non lined socket and man oh man she ran like a bag of sh..I pulled them all just to check the condition, but ended up cracking one. I pulled all my plugs again and checked, but found nothing so I stuck them back in thinking it was the wires. I replaced the wires and it still didn't improve. I then bought all new plugs and the problem went away. I checked my old plugs again and found a nice little crack in the side of one of them!

I agree with Wiswind, if you don't use the Autolite or Motorcraft plugs, they will work, but they will not last as long as they should. I used Bosch triple tipped platinum and they lasted about 30 to 40,000 km before the electrode tips were completely gone (I mean eaten right up inside the ceramic!).

i had a similar problem and it turned out to be the coil pack,,,,,,it caused a misfire on my no. 3 and rough idle,,,replaced it and was fine found one on e bay for 35 or 40 bucks on abc parts

i had a similar problem and it turned out to be the coil pack,,,,,,it caused a misfire on my no. 3 and rough idle,,,replaced it and was fine found one on e bay for 35 or 40 bucks on abc parts

Hi all first post. Is there a way to determine if the coil pack is bad besides buying a new one and trying it? I have a mulitmeter so I can check resistance, etc. but Im not sure what I should look for. The orginal problem was getting a misfire on #3, ive already replaced the plugs and cables, plug gap was confirmed correct. Then I started to get an" engine running lean" fault and the misfire on #3 according to autozone. Any help would be appreciated!

Hi all first post. Is there a way to determine if the coil pack is bad besides buying a new one and trying it? I have a mulitmeter so I can check resistance, etc. but Im not sure what I should look for. The orginal problem was getting a misfire on #3, ive already replaced the plugs and cables, plug gap was confirmed correct. Then I started to get an" engine running lean" fault and the misfire on #3 according to autozone. Any help would be appreciated!

Hello g00fball, welcome to the forum!

Please avoid "bringing threads back from death", since this post has more than one year you'll be better starting a new thread and if it's necessary paste a link to the old thread.

About your problem, here are the instructions on how to test the coil pack:

The pins on the back are the 3 PRIMARY COILS which all tied together on one side (Pin #4) and the other side goes to the PCM (which applies either ground or voltage) for firing order. These should be within .3-1.0 Ohms.

The big lugs at the front correspond to the 3 SECONDARY COILS this are physically separated from the primary coils, the magnetic field of the primary coils is induced into the secondary coils and that's what produces the voltage for each pair of cylinders (the engine fires 2 cylinders at a time)

What elevates the voltage from 12v to several thousands is the number of turns of the primary coil in relation with the number of turns of the secondary coil: if the primary has 10 turns and the secondary has 100 turns you'll have 10 times more voltage at the secondary than the primary.

After the theory let's go back to your problem. the readings for the second step should be taken from the big lugs at the top of the coil pack:

1 2 3
O O O --> COIL PACK LUGS
O O O --> COIL PACK LUGS
4 5 6

You should connect your multimeter between 1-4, 2-5, 3-6; each pair of lugs corresponds to the terminals of each secondary coil and the readings should be 10k to 12k Ohms.

NOTE: the numbers have been used randomly, these do not correspond to the actual cylinder number.

Another way to test an arching coil pack is by spraying water around the coil pack, you should see sparkles coming out and arching nearby.

Best regards,

Oscar.

A common failure on the newer Windstars is the coil pack.
The problem that seems to be reported is that a crack develops in the epoxy body around the coils.
When this happens, they will still ohm out just fine, but the high voltage can arc through the crack, instead of across the gap in the spark plug.

With a lean code, another thing to try would be the fuel system cleaner.
Has the fuel filter been replaced recently?.....if not......that would be another idea.
It is possible that the fuel pump is not delivering enough fuel pressure.

A dirty fuel injector can cause misfire code(s) as well as the lean code(s).
This is why I recommend the fuel system cleaner.....cheap and easy.

A vaccum leak can also cause lean code(s) as well as misfire codes.

Hi all first post. Is there a way to determine if the coil pack is bad besides buying a new one and trying it? I have a mulitmeter so I can check resistance, etc. but Im not sure what I should look for. The orginal problem was getting a misfire on #3, ive already replaced the plugs and cables, plug gap was confirmed correct. Then I started to get an" engine running lean" fault and the misfire on #3 according to autozone. Any help would be appreciated!

I don't think that the coil pack is your problem. My reasoning is that the coil pack wont work any better after the engine is warmed up. Secondly, I replaced my coil pack on my 2001 earlier this year to correct its bad running (which it did fix) but now am having the exact same symptoms that your are having. Starts fine, drive about a mile, sitting at idle at the traffic light for a minute and then starts running horrible. Putting it in neutral while stopped may help. Once in drive and going along everything is fine again and no CEL or trouble codes at this event (but occasionally getting 171/174). That being said, if you have over 100k, your coil pack is likely running on borrowed time.

I will be investigating this problem at the same time that you are so I am interested in what you find out. I can see that it could be EGR related, since the EGR should be opening once the operating temperature is reached, maybe around the time that the van sits at the traffic light. Alternatively, it could be a symptom of the 171/174 upper intake gasket.