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Misfire in #4 code, can't solve

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  • Author

Ok, so it COULD be the wires, even though they charge and arm and an rump roast at Napa! I get a 20% discount and they were still more than OEM!

How often do you recommend a change?

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Yes, Nipper, that link does cover a lot of basic info. Most of it is accurate, but there are a few errors and misconceptions. Some aren't too important (it's "Tesla", not "Teslar", and electromagnetic interference is "EMI", not "EMF", which is electromotive force).

 

Some statements are misleading. An example from the section on point dwell is "The ratio of closed points to open is usually about 3:1.". While that ratio can vary depending on application, it's more typically about 2:1. Under "Common problems with a conventional ignition system are:" is "Timing belt (chain) wears and/or breaks "; well, as we know, that isn't limited by the type of ignition.

 

Still, not a bad article, but I'd suggest reading it with a grain of salt.

 

Its the best I could find that wasnt from my own brain :)

 

Its also a bit old, but i was only looking for wire info ...

 

nipper

Ok, so it COULD be the wires, even though they charge and arm and an rump roast at Napa! I get a 20% discount and they were still more than OEM!

How often do you recommend a change?

 

Always USE oe on subarus, ESPECIALLY if OE is cheaper. I change mine once every 100,000 miles, or if the car gives me a reason to change them.

 

nipper

 

wow i wonder what kind of mark up NAPA is getting.

  • Author
Always USE oe on subarus, ESPECIALLY if OE is cheaper. I change mine once every 100,000 miles, or if the car gives me a reason to change them.

 

nipper

 

wow i wonder what kind of mark up NAPA is getting.

 

 

$72 with discount!

subie was 60 (BEFORE discount!)

  • Author

So in your professional opinion, do you think this could be it? the wires that is/

If the wires you have on there now are fairly new then I myself doubt that new wires will fix this. I could be wrong though. I would more suspect carbon buildup or valves causing this.

  • Author

Wouldn't I be able to check by swapping #2 to #4 wire?

then re-read the code after it shows up again?

 

Or is it possible that a carbon build up presented due to a poor firing due to the faulty Coil? Therefore the initial problem is fixed (new coil), but before the fix, it caused a secondary problem?

 

 

am I thinking down the wrong path here?

 

I am trying to learn how a professional thinks, that is why I ask so many questions.

You can swap wires, but you have to swap those two first, then leave themswapped and swap the wires on the other side. This is a waste spark ignition, so 1-2 and 3-4 fire together.

 

nipper

  • Author

ok, I will get a read, reset, and then make both swaps.

thanks

If its a missfire you can't feel, dont forget to clear the codes too.

 

nipper

  • Author
If its a missfire you can't feel, dont forget to clear the codes too.

 

nipper

 

yup.

I appreciate all the help.

  • Author

Read the codes yesterday at advance auto. same "S" P0304

so the wires are on the way. if that doesn't work, ? well, maybe that front O2 sensor then Valve adjust if all else fails...

 

If that fails, leave the keys and drop the car in the hood I guess!

i hadthe#4 misfirecode onmy 01 outback... only 65k miles... i went as far as swapping an injector with #2.. then i swapped the #4 WITH #2 WIRE.. reset and drove.. code flipped to #2 cyl.. so i knew it as the wire.. wven tho it woud shoot spark out the end of the wire 4" lol..

 

try swapping #2 ad 4 wires.. reset the ecu and see what pops code wise.. that will rule out the wire issue..

Ok, so it COULD be the wires, even though they charge and arm and an rump roast at Napa! I get a 20% discount and they were still more than OEM!

How often do you recommend a change?

 

i have seen NEW aftermarket wires cause cylinder misfire codes. replace the wires and codes go away. others have had it happen as well. this isn't Subaru specific - it's EJ engine specific, they are not forgiving engines when it comes to ignition wires.

 

i can't promise this is your problem, but i have seen it before....hopefully someone can help you diagnose more to pinpoint it. the wire swap should help show a bad wire.

If the wires you have on there now are fairly new then I myself doubt that new wires will fix this. I could be wrong though. I would more suspect carbon buildup or valves causing this.
while I have seen new wires cause this, i do agree that there's a good chance new wires won't fix it. particularly being NAPA brand, i've never seen them, but would think they are better than others.

 

a simple wire swap should take less than one minute and cost nothing. reset the codes and see if it "moves" with the wires.

  • Author

I did this and it didn't change things. But I have since replaced the ignition coil.

Gonna try it all, if it ever gets above 10 here!

I lost access to my heated garage when my buddy flew south for the winter.

If that front 02 sensor is older than 40k miles, maybe replace it. My 2001 Forester demands a new one every 40k. But I do mostly city driving.

  • Author
If that front 02 sensor is older than 40k miles, maybe replace it. My 2001 Forester demands a new one every 40k. But I do mostly city driving.

 

Does that throw an independant code? or just the misfire code? P0301,2,3,4

Does that throw an independant code? or just the misfire code? P0301,2,3,4

 

Usually, if you use an OE o2 sensor, it will last way beyond 100,000 miles. Mine lasted 180,000, and it saw a hell of a lot of NYC driving (you dont get much more city then that).

 

Th o2 sensor usually throws its own code unless its long in the tooth, and getting lazy. there are tests with a multimeter you can do check the sensor.

 

 

nipper

  • Author

my front sensor has at least 80k on it, that's the amount since I got it.

but I guess, since they last up up to 180, purchased at 140k, it could be original.?

what is the test?

  • Author

ok, swapped plugs and wires to OEM and NGK platinum

drove ~325 miles. no light, left the station after gasin up, less than a mile light back on. THIS HAPPENED while accelerating from a dead stop.

also the gas mileage has dropped to 23ish highway, from ~26.5

 

preach away

sorry Garth, I know you do not like being

"preached to"

 

You will need to see what code is stored now.

 

You can not just assume it's the same one.

Maybe you left the gas cap loose - for instance.

  • Author

Sorry I didn't note that I checked when I got home. same "S" P0304

misfire #4

I'd say, time for a Diamond coil pack.

 

I saw you changed it but did not see what brand or from where.

 

Plus I think you should listen to

WAwalker and his valve adj advise.

 

He is one of THE best techs we have here.

 

This seems to have been dropped back on page one.

 

 

If you did have them checked/done and I missed it,

I apologize.

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