03 windstar rough idle working bad,worse in the rain

Take your car for a compression test to see if there is any vacuum leak causing the engine to run rough. Also, this could be due to a bad MAF sensor or an O2 sensor. If the check engine light is ON, you should better get the codes read.

My uncle worked at a dodge dealership as a head mechanic for over 30 years and he also found all of the 3.9 liter engines to have the rough idle. The rough idle cannot be explained but it can be made worse by buildup on the engine. I have a 2001 Dakota sport with the 3.9 and mine does it too and one of the first times i drove it it stalled and its not a Manuel transmission. But onc I changed the oil and put Lucas oil additive as well as regular additives to my gas every month or so it has reduced greatly and not stalled since. Hopefully you find this helpful.

Do you have a scan tool that can read sensor data PID'S ? 080 EGR and Catalytic Converter Tests EGR Test

when I changed plugs one was a little wet. help Leaking fuel injector .

I have a 2003 ford windstar.Engine started to run rough when it
used to rained.I would accelarate it until roughness would go away sort of.It lack a little power but if I take it a mechanic they would charged too much money.Anyway, the problem was a spark plug wire in front of the engine, wires that are grouped together with that little pin. One of them was rubbing agains the valve cover and it got worned out current would leak out right there.I discovery it one time that it rainned really hard I had to go out and the wagon started to miss really bad and it wouldn't move.Finally, I got home the next day I looked under the hood to see what I can see and there it was a spark plug wire that one can tell if you know a little bit about cars that current was leaking throw it. I replaced wire problem solved.But now after all of that snow we had the check engine light came on and I am not sure what could be.For I remmerber running over a mountain of sort of hard snow.So it probably broke oxigine sensor wire.

Try swapping the injector on that cylinder with the one next to it and see if the misfire changes to the other cylinder.If it does then you have a plugged or bad injector.It it still stays on that same cylinder then check compression on the number 6 cylinder.Let me know what you find out.Good luck.

heh, you might want to change the title here as I am pretty sure you cant idle under heavy acceleration.
However I think you were on the right track with the plugs and wires. You didnt mention the cap though and that is usually the biggest culprit in damp weather. Put a new cap and rotor on it and see if that doesnt do the trick.

Most common fault is the distributer cap.You want loose nothing by changing it,Has they are supossed to be changed at high milage.

try disconnecting the vacuum line from the EGR valve and drive it to see if it makes a difference

Check, clean EGR valve & see if that helps.

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