301 code

[fy171]

last week engine started to run rough when i hit the gas it would go away,felt like one plug not fireing,low idle it runs rough hit the gas and runs smooth, last may did 171,174 fix allso change plugs and wires wich mad the engine much smoother use double plat plugs, the cel whould flicker for a few minutes then on steady clear code ran a few days good them same thing happens runs smooth after 10 minutes starts to feel the miss,301 is plug #1 not fireing what should i start to look for,beside the plug and wire.

thanks frank 2002 windstar 78k

[fy171]

ran couple of daysa ran fine then rough missfire came back code301 clear code and runing smooth again
i think it has to be coil pack

[serge_saati]

Yes, maybe the coil pack.
Have you replaced your alternator recently? Cause a bad alternator can cause some damages.

[wiswind]

P0301 is a misfire detected on cylinder #1.
Cylinder #1 is in the rear bank of cylinders.....driver's side.
When the misfire is actually happening, the CEL will FLASH as a warning that it is a problem that can damage the Catalytic Converter(s).

Then the CEL will STAY lit for a given amount of time that there is NO additional failure.

If the cause is from no spark, then raw fuel can be entering the catalytic converter.....which can cause it to overheat.
If the cause is from a dirty fuel injector......lack of fuel in the cylinder....then that would not damage the catalytic converter....as the cause of misfire is NO FUEL to ignite.

As mentioned, a spark plug, spark plug wire, or coil pack are likely causes for lack of spark.
YES, it is possible for the coil pack to cause a problem with only 1 cylinder.
Humid/wet conditions often cause spark issues to be worse.

Clogged EGR ports can cause a misfire...although that usually happens on cylinder(s) 3 and/or 4.

A dirty fuel injector can cause a lack of fuel.......the only thing that I have found that will clean fuel injector deposits on my '96 is Berryman's B-12 Chemtool added to the gasoline tank.

This would also be a very good time to replace the fuel filter if it has not been replaced in the past year.
A clogged fuel filter not only can restrict the available fuel to the engine, it adds an additional work load onto the fuel pump....which could shorten the life of it.

[serge_saati]

Originally Posted by wiswind

P0301 is a misfire detected on cylinder #1.
Cylinder #1 is in the rear bank of cylinders.....driver's side.

Nope, it's on passenger side.

[wiswind]

Correct.......I stand corrected.
This would make clogged EGR ports a possible cause.
The EGR ports star clogging on the driver's side.....closest to the EGR valve FIRST.
This leaves Cylinders #1 and #4 the last ones open (not #3 and #4 as I have stated in the past).
With all the EGR flow pushing into the intake through these 2 ports.....one or both of these cylinders is getting a high amount of oxygen starved air (from the exhaust) and you get no ignition due to lack of oxygen.

The way to test to see if it is being caused by clogged EGR ports.....
TEMPORARILY remove and plug the vaccum line that goes to the top of the EGR valve.
(This will disable the EGR valve from opening......no EGR flow......should cause a code and CEL for this).
Take the vehicle for a drive.....
Still have the misfire Yes.....then it is not being caused by clogged EGR ports.
NO......Then the cause is most likely due to clogged EGR ports.
Re-connect the vaccum line to the EGR valve.

To clean the EGR ports, you have to remove the upper intake manifold....
There is a small 1/4" port in each of the intake ports that does NOT have the IMR plate.
Just use a small poker to break loose the crud.....and suck it up with a vaccum.
Avoid getting any junk down into the intake.
The blockage is ONLY right at the very end of the port.....as it enters the intake.
On down inside the EGR passage will be fine.

There is no spray into the intake or add to the fuel cleaner that will clean the EGR ports.....
It has to be done manualy.

[fy171]

the first time this problem started it was raining,dry weather ran fine ,then next time it was raining had same problem ,third time same thing only when its damp out i have the problem makes me to believe that this is a ignition problem,spark plug ,wire or coil,replace plugs and wire in june when i did the fix for p171/174, am i on the right track for this
thank you

[fy171]

today went out and it was raining and same thing is happening

[tempfixit]

When you replaced wires in june did you apply diaelectric grease to wire boots??

[serge_saati]

Try to spray WD-40 on the plugs wires insulator. Not in inside of the contact.
It sounds weird, but oil removes moisture and prevent electrons to get out of the wire.
Just the vapor of the WD-40 is enough to dry the engine compartment.

It also prevents parts to rust. Spray all around uder hood exept on belt, nylon and contact.

[fy171]

tempfixit yes i did apply diaelectric grease to wire boots,

thank you

[tempfixit]

Another thing you could try is when it is dry out and running fine take a spray bottle and spray on mist on the wires at the plugs, if that doesn't cause the problem work your way to the coil pack and see if you can duplicate the problem.

good luck

[fy171]

replace coil pack today ,plug and wire was ok, seems like it felt that it had a little more power and ran smoother ,will see if i get the 301 code again

thanks frank

[wafrederick]

If it comes on again,remove the upper intake and you will find plugged up EGR ports and is a known problem.Seen this happen on another windstar which it was not plugs and wires

[fy171]

thanks wafrederick,i did clean the egr ports in june when i did the 171/174 fix and the ports were clean then ,but will check it again if the 301 code pops up again

thanks frank