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Misfire wont go away! Help!


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33 replies to this topic

#1 cascadeclimbn

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Posted 01 May 2014 - 12:17 PM

I own a 96 impreza outback wagon. I have a misfire that keeps bouncing around cylinders and comes back everytime I replace something. Last month I replaced the plugs because of a misfire in cylinder 2 I believe...the car ran fine for a week. Then CEL came on again and showed another misfire so I replaced wires. After the wire swap it ran fine for another two weeks and started having the same problem with the CEL showing at first a misfire in cylinder three then 2 days later a misfire in cylinder's 3 and 4 so this led me to believe that if there were misfires in both 3 and 4 which run off the same side of the coil pack that it has to be the ignition coil...this morning i put on a new ignition coil and not more than 10 miles down the highway the problem came back and is now showing a misfire on cylinder #1. The whole time the symptoms have always been that the car will start running rough and shaking and not accelerate with rpm's especially at higher speeds and on steeper grades. The car will also have some slight smoke from underneath the engine after the CEL starts flashing. The girl at Autozone thinks its a fuel injector but that doesnt make any sense to me unless it would be that all 4 fuel injectors need replaced. Any ideas? 



#2 grossgary

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Posted 01 May 2014 - 12:24 PM

any other check engine lights other than misfires?

 

what plugs and wires did you use?

 

NGK plugs

High quality wires

 

Maybe the igniter on the firewall.

 

Check fuel pressure - make sure it's not running lean. Fuel filter ever been replaced?



#3 cascadeclimbn

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Posted 01 May 2014 - 12:43 PM

any other check engine lights other than misfires?

 

what plugs and wires did you use?

 

NGK plugs

High quality wires

 

Maybe the igniter on the firewall.

 

Check fuel pressure - make sure it's not running lean. Fuel filter ever been replaced?

grossgary, when I bought the car about 2 months ago it did have 2 other codes at the time--a MAP sensor which was resolved by reconnecting a vaccum line that'd come undone and a knock sensor code which was resolved by replacing the faulty knock sensor...neither of those issues have returned since fixing the first time 1000+ miles ago of which there havent been any other check engine lights since other than the multiple misfire's. I used Duralast wires and NGK V-Power plugs and today I bought a Duralast ignition coil b/c its the only one in stock within 25 miles.

 

I have not replaced the fuel filter and dont know if the previous owner ever did...what problem could that be causing? Maybe I'll try and replace that today.

How do I check fuel presssure?

Is there a way to test the ignitor?



#4 cascadeclimbn

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Posted 01 May 2014 - 03:32 PM

So I'm going to pour a pint of seafoam into my gas tank and see if that helps anything till I can go over to my stepdads Sunday and check compression and fuel pressure. In the meantime does anyone else have any ideas on what to check/replace?

#5 grossgary

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Posted 01 May 2014 - 03:44 PM

seafoam isn't a bad idea at all.

 

while i doubt that's the issue, i wouldn't be fully confident in the duralast wires *on this engine*.  EJ engines are unforgiving of low grade wires. other subaru engines could run with coat hangers for ignition wires (lol), EJ engines not so much.  i've seen *brand new*, right out of the box, low end wires cause misfires on EJ engines.

 

again, probably not it, but hard to rule out with those engines (or emissions requirements, whatever caused it), being kind of picky with ignition.



#6 cascadeclimbn

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Posted 01 May 2014 - 04:52 PM

seafoam isn't a bad idea at all.

while i doubt that's the issue, i wouldn't be fully confident in the duralast wires *on this engine*. EJ engines are unforgiving of low grade wires. other subaru engines could run with coat hangers for ignition wires (lol), EJ engines not so much. i've seen *brand new*, right out of the box, low end wires cause misfires on EJ engines.

again, probably not it, but hard to rule out with those engines (or emissions requirements, whatever caused it), being kind of picky with ignition.


I keep hearing that about the wires from a lot of folks on here. You really think it could be the wires? If that's the case I suppose I'll pick up a new set of oem's at the dealer tomorrow.

#7 willwright

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Posted 01 May 2014 - 05:35 PM

The fact that the misfire is jumping around really makes me think wires and or plugs. Dealer plug wires ran me 44 dollars not even 2 weeks ago so not much more than box store wires. I had autolite plugs in mine and they went to crap very quick. I put the NGK platinum it calls for and the car rums like it never has before. I second a couple tanks with seafoam and change fuel filter. I would try and get away with changing fuel filter after the seafoam in case it removes a bunch of crap from tank and lines. Fuel filters aren't that expensive regardless so you could do it either way. I would think because misfire jumping around, it would NOT likely be injectors but could be a weak fuel pump. Not having any other codes doesn't lead me to think its any other sensors. Make sure those plug wires are snapped onto those plugs, when I pulled those autolites , I had actual looked like burn streaks down then side of my number 3 plugs where the spark was jumping down the side of the plug. Keep us updated and good luck.

#8 belacane

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Posted 01 May 2014 - 05:49 PM

I had this issue of random misfires that would come and go with my 02 Impreza WRX and it turned out that the air inlet between the MAF/air filter and the throttle body was creased where it met one or the other (I forgot which). 

I ended up finding the problem when I went to replace the engine air filter.  

 

It's pretty far off the mark based on what other people are saying, but I'm just throwing it out there in case it might help.


Edited by belacane, 01 May 2014 - 05:50 PM.


#9 cascadeclimbn

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Posted 01 May 2014 - 10:24 PM

The fact that the misfire is jumping around really makes me think wires and or plugs. Dealer plug wires ran me 44 dollars not even 2 weeks ago so not much more than box store wires. I had autolite plugs in mine and they went to crap very quick. I put the NGK platinum it calls for and the car rums like it never has before. I second a couple tanks with seafoam and change fuel filter. I would try and get away with changing fuel filter after the seafoam in case it removes a bunch of crap from tank and lines. Fuel filters aren't that expensive regardless so you could do it either way. I would think because misfire jumping around, it would NOT likely be injectors but could be a weak fuel pump. Not having any other codes doesn't lead me to think its any other sensors. Make sure those plug wires are snapped onto those plugs, when I pulled those autolites , I had actual looked like burn streaks down then side of my number 3 plugs where the spark was jumping down the side of the plug. Keep us updated and good luck.

I think fuel pump and fuel filter will be were I focus tomorrow. Thanks for the advice.


Edited by cascadeclimbn, 01 May 2014 - 10:26 PM.


#10 cascadeclimbn

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Posted 01 May 2014 - 10:33 PM

So upon recommendation from this site I went and got better plug wires. None of the auto part stores had any NKG's in stock and it would have taken min., 2 days for them to come in and the Subie dealership didnt have OEM's in stock either so I went with a set of Intermotor Premium wires. They were $48 (about the same price as NKG's) and the guy at Cut Rate Auto said he liked them way better than NKG's. They are made to exact OEM specs. Put them on started up the car and immediately noticed a big difference...these wires are good. But, unfortunately not my problem as the misfire in cylinder 1 from this morning has now come back as a misfire in cylinder 3. Tomorrow I'm going to look in to replacing the fuel pump and Sunday I'm gonna check compression. Anybody have anything else to add or any ideas as to what could be going on? Also, what is the worst case scenario I could be facing with misfires jumping from cylinder to cylinder, car shaking and losing acceleration power?



#11 cascadeclimbn

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Posted 01 May 2014 - 10:35 PM

Does anybody else think my problem could be the fuel pump? Any way to check before dropping $120 on a new one?



#12 ocei77

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Posted 02 May 2014 - 09:55 AM

Am having similar issues tracking down a misfire on a 96OB. Have done all that you have done. My next item is changing the crank sensor. I'd check your fuel pressure since you have the ability to do so. I also notice that you have not changed your fuel filter. Do so. A partially gunked up filter will not let fuel flow consistently.Unless you can rule this out, a fuel pressure test won't be conclusive.

 

O.



#13 Prwa101

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Posted 02 May 2014 - 11:08 AM

Were the coil pack plug connectors corroded at all? Did you clean them?

Edited by Prwa101, 02 May 2014 - 11:08 AM.


#14 cascadeclimbn

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Posted 02 May 2014 - 01:36 PM

Am having similar issues tracking down a misfire on a 96OB. Have done all that you have done. My next item is changing the crank sensor. I'd check your fuel pressure since you have the ability to do so. I also notice that you have not changed your fuel filter. Do so. A partially gunked up filter will not let fuel flow consistently.Unless you can rule this out, a fuel pressure test won't be conclusive.

 

O.

I bought a fuel filter last night and will be changing that this afternoon when I get home...it'd be real nice if that little thing was the issue (fingers crossed). What made you think your problem was the crank sensor?



#15 cascadeclimbn

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Posted 02 May 2014 - 01:37 PM

Were the coil pack plug connectors corroded at all? Did you clean them?

Good point. I didn't even check the electrical connector that runs from the engine bay. Ill take a look today. Although when I tested the old coil pack I didnt notice any corrosion on the connector coming of the coil pack.



#16 Prwa101

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Posted 02 May 2014 - 03:42 PM

I ment where the plug wire, plugs into the coil pack. lol the brass nubs

reps504603_1.jpg



#17 cascadeclimbn

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Posted 02 May 2014 - 03:48 PM

I ment where the plug wire, plugs into the coil pack. lol the brass nubs

reps504603_1.jpg

Ah okay. Well my 96 OBW's coil pack has the female connector...opposite of the one in the photo. I think those are on just the outback wagons. At any rate, still didnt see any noticeable damage to the coil pack itself.



#18 Prwa101

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Posted 02 May 2014 - 03:54 PM

I figured itd be the opposite on of what i posted haha.

 

Did you look in the female ends? make sure you look in them all. 



#19 cascadeclimbn

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Posted 02 May 2014 - 07:57 PM

I figured itd be the opposite on of what i posted haha.

Did you look in the female ends? make sure you look in them all.


I checked and there was no corrosion. Just put in a new fuel filter and Pcv valve and am about to test drive it. The old fuel filter looked like it hadn't been replaced in a very long time but the gas that poured out looked clean to me (though I probably don't know what I'm supposed to be looking at). The Pcv valve looked like a disaster though and perhaps has never been changed. Lots of nasty sludge and other particulates inside it and I have it a shake and didn't hear any moving parts. Will report back on how the test drive went in like a half hr.

#20 willwright

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Posted 02 May 2014 - 10:42 PM

Clean the heck out of that egr and all that's related to it if its as bad as you say. That's one thing I don't really like about the Subaru is the fact they don't like anything to be out of whack so to speak. When something is wring, it seems there is no golden bullet, its a allow process of elimination and one thing wrong seems to throw a code for something else because that part is not working correctly. When we finally get them figured out there is nothing that rums better or smoother than these subies. Don't give up on it or get frustrated, eliminate one thing at a time and we will figure it out.

#21 ocei77

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Posted 03 May 2014 - 11:24 AM

Before I changed my crank sensor, I double checked my timing and it is off. Will have to wait until I get back to the garage on Mon to reset.

I wanted to change the crank sensor because that controls spark. If it is failing you can get sporadic, but consistent misfires. It's not a common failure, but I was going down my list.

So, check your timing.



#22 cascadeclimbn

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Posted 03 May 2014 - 03:49 PM

Clean the heck out of that egr and all that's related to it if its as bad as you say. That's one thing I don't really like about the Subaru is the fact they don't like anything to be out of whack so to speak. When something is wring, it seems there is no golden bullet, its a allow process of elimination and one thing wrong seems to throw a code for something else because that part is not working correctly. When we finally get them figured out there is nothing that rums better or smoother than these subies. Don't give up on it or get frustrated, eliminate one thing at a time and we will figure it out.

Thanks willwright! I havent cleaned the egr valve yet but plan on doing that tomorrow...what else do you reccomend going thru and cleaning up? And do I just clean the EGR with brake fluid?



#23 cascadeclimbn

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Posted 03 May 2014 - 04:06 PM

So here is my update on the test drive from yesterday: After changing the fuel filter and pcv valve I took it out on the highway and within 5 miles it started having the same symptoms (car shaking, erratic shifting, loss of acceleration) but this time it didnt throw a check engine light and "drove out of it" so to speak so I kept driving then another 15 miles down the highway the same thing happened again except this time the symptoms did lead to a flashing CEL and I had to pull over for 10 minutes. I drove it down the back roads back to the closest auto parts store where the read the CEL and it was another misfire code in cylinder 1. Funny thing is, when I left the auto parts store the CEL dissapeared from my dash and the car seemed to drive normal again so I decided to take it back on the highway and drove for an hour at 60-70mph with no problems--I was close to my parents house so I drove there and my stepdad helped me check compression, fuel pressure, and vaccum. I couldnt find the specs anywhere so can anyone tell me if this checks out: Compression was around 175-80 in all cylinders, fuel pressure was steady at 28psi, and vacuum (here at sea level) was 27. Can anyone tell me if all that is within range? Also can anyone tell me why I would have the same symptoms after changing the fuelk filter and pcv valve for the first 15 miles and then the next 175 miles of highway driving no issues at all? I even took it up a long steep hill that I never make it up without triggering the CEL and it did absolutely fine. I don't know if I fixed it, masked the problem, or just got lucky for a few miles. Any dieas/opinions/thoughts, etc are appreciated.


Edited by cascadeclimbn, 03 May 2014 - 06:25 PM.


#24 willwright

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Posted 03 May 2014 - 05:56 PM

Not sure what engine you have but the 2.5 is 156-185 psi. Did you squirt a little oil in each cylinder to see if compression would come up as well? If you used oil in cylinders and compression comes up a lit then compression rings are worn out. If its slow to build compression its a sign of valves not sealing. 75-80 is at least even but sounds pretty low to me but don't take that to the bank because I'm not sure what engine you have.

#25 cascadeclimbn

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Posted 03 May 2014 - 06:02 PM

Not sure what engine you have but the 2.5 is 156-185 psi. Did you squirt a little oil in each cylinder to see if compression would come up as well? If you used oil in cylinders and compression comes up a lit then compression rings are worn out. If its slow to build compression its a sign of valves not sealing. 75-80 is at least even but sounds pretty low to me but don't take that to the bank because I'm not sure what engine you have.

I have the EJ22...built before 6/1996






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