Never Ending Misfiring...
07-28-2010, 10:15 AM
#1
Never Ending Misfiring...
I have been battling a cylinder 6 misfire (P0306) for many months now. I have spent a lot of time on this website researching, but I can't seem to find anything that works.
The problem: Intermittent misfiring on cylinder 6 that will come and go. It can switch from misfiring to not misfiring instantly. No change due to driving conditions. It happens on the interstate at 70mph, in neighborhoods at 25mph, and at idle. Some days it runs great, only misfiring for a short time, other days its a battle all day long. Sometimes it accelerates just fine, other times it misfires all the way. The idle is fine. Although it may misfire, the idle stay very normal, no fluctuation.
I have checked the easy stuff already:
-Purchased new OEM coil and installed on cylinder 6
-Switched out new coil from cylinder 6 with a coil from a known good cylinder
-Replaced all 6 spark plugs
-Switching spark plugs between cylinder 6 and known good cylinder
-Switched fuel injectors from cylinder 6 with a known good cylinder
-Tugged and pulled on the wiring harness from the front bank of cylinders all the way back to the firewall by the passenger side strut tower
-Sprayed starting fluid all around intake plenum, no change in idle
-Flashed ECU to updated version
I have done all of the above, and none have made any difference in the misfiring. Always on cylinder 6.
I, fortunately, know a tech at the local Nissan dealership who also tested the the wiring harness and intake plenum with similar results. He also flashed my ECU. He is now saying it's the ECU because none of the other things have fixed it. His cost on the ECU is $650!
I called David from SpeedometerRepairGuy.com and explained what I needed and he said the ECU rebuild he does for Maxima's wouldn't fix my misfiring (only fixes damage from a bad IACV), also stating he had never heard of this problem before. Again, I have no problem with my idle.
Not sure what to try next. A friend of mine suggested the fuel filter, but the Nissan tech was adamant that it couldn't be the fuel filter, also citing its a "lifetime" part. Thought about just changing it, since it's so cheap anyways.
Any other ideas of things I should try before getting a new (or used) ECU? I have already purchased one used ECU through car-parts.com and it was bad, so I am 1) trying avoid the hassle of trying to find a good used ECU and 2) trying to avoid spending $650+ on a new ECU from Nissan. After all, at this point, I don't know it's a bad ECU, it's by deduction that I/we think its the ECU.
The last thing I want to happen is to replace the ECU, and it still misfires.
Edit: I have a 2001 SE automatic transmission, no traction control. 102k miles. It is also throwing a P0430, but I am assuming that is 1) "normal" problems with the pre-cat 2) damage from the mis-firing.
The problem: Intermittent misfiring on cylinder 6 that will come and go. It can switch from misfiring to not misfiring instantly. No change due to driving conditions. It happens on the interstate at 70mph, in neighborhoods at 25mph, and at idle. Some days it runs great, only misfiring for a short time, other days its a battle all day long. Sometimes it accelerates just fine, other times it misfires all the way. The idle is fine. Although it may misfire, the idle stay very normal, no fluctuation.
I have checked the easy stuff already:
-Purchased new OEM coil and installed on cylinder 6
-Switched out new coil from cylinder 6 with a coil from a known good cylinder
-Replaced all 6 spark plugs
-Switching spark plugs between cylinder 6 and known good cylinder
-Switched fuel injectors from cylinder 6 with a known good cylinder
-Tugged and pulled on the wiring harness from the front bank of cylinders all the way back to the firewall by the passenger side strut tower
-Sprayed starting fluid all around intake plenum, no change in idle
-Flashed ECU to updated version
I have done all of the above, and none have made any difference in the misfiring. Always on cylinder 6.
I, fortunately, know a tech at the local Nissan dealership who also tested the the wiring harness and intake plenum with similar results. He also flashed my ECU. He is now saying it's the ECU because none of the other things have fixed it. His cost on the ECU is $650!
I called David from SpeedometerRepairGuy.com and explained what I needed and he said the ECU rebuild he does for Maxima's wouldn't fix my misfiring (only fixes damage from a bad IACV), also stating he had never heard of this problem before. Again, I have no problem with my idle.
Not sure what to try next. A friend of mine suggested the fuel filter, but the Nissan tech was adamant that it couldn't be the fuel filter, also citing its a "lifetime" part. Thought about just changing it, since it's so cheap anyways.
Any other ideas of things I should try before getting a new (or used) ECU? I have already purchased one used ECU through car-parts.com and it was bad, so I am 1) trying avoid the hassle of trying to find a good used ECU and 2) trying to avoid spending $650+ on a new ECU from Nissan. After all, at this point, I don't know it's a bad ECU, it's by deduction that I/we think its the ECU.
The last thing I want to happen is to replace the ECU, and it still misfires.
Edit: I have a 2001 SE automatic transmission, no traction control. 102k miles. It is also throwing a P0430, but I am assuming that is 1) "normal" problems with the pre-cat 2) damage from the mis-firing.
Last edited by dustey; 07-28-2010 at 10:18 AM.
07-28-2010, 11:13 AM
#2
Senior Member
Join Date: Mar 2004
Posts: 497
Get the compression readings, both dry and wet. It is highly unlikely that ECU is your problem. ECU does not have any special code for cylinder #6. You have already verified that both ignition and injector wiring to that cylinder are intact.
- Vikas
- Vikas
Last edited by sontakke; 07-28-2010 at 11:18 AM.
08-27-2010, 11:11 AM
#3
To follow up on this thread, I checked the compression (dry) and it was 125 across the board. Low, but not inconsistent which is good.
Despite the Nissan tech's advice to not replace the fuel filter (strainer) since it's a "lifetime" part, I did anyways because it was a $13 part, easy to do, and $13 isnt a lot to take a chance on in case it does work.
I did both the compression test and fuel filter last Thursday (8/19/10) and it hasn't misfired since. Unbelievable.
Despite the Nissan tech's advice to not replace the fuel filter (strainer) since it's a "lifetime" part, I did anyways because it was a $13 part, easy to do, and $13 isnt a lot to take a chance on in case it does work.
I did both the compression test and fuel filter last Thursday (8/19/10) and it hasn't misfired since. Unbelievable.
08-27-2010, 12:43 PM
#4
Nice lol. For all it's worth, when I got my maxima 4 months ago, i was gettin a random misfire code. Since then, all I did was change my spark plugs and ran some seafoam in it then did an oil change. (Stupidly changed my spark plugs first so i ended up taking them out and putting the old ones in for seafoaming and then replacing again. yes it was a big waste of time ) Haven't had a CEL in the last 3000 ish miles
08-27-2010, 01:07 PM
#5
i would recommend a leak down test now...i had this problem in two cylinders...passed compression test...failed leakdown test...replaced plugs and coils and had the same problem...mine was caused by the plugs getting covered in oil from the bad rings...
08-27-2010, 09:41 PM
#6
I don't have any oil on my plugs. Would a leak down test really help anything?
09-09-2010, 07:20 AM
#7
Update #2: It has started misfiring again. 
It started doing it on Friday 9/3/10. It went 2 weeks without misfiring, and started back again. The frequency seems to be less, however it is throwing the P0306 code again (same cylinder as before). Since the problem started however long ago, it hasn't gone that long without misfiring. It leads me to believe that its fuel related somehow.
A friend suggested that it may be caused by a dirty fuel tank... reasoning that it ran fine for 2 weeks with a brand new fuel filter until it reached the dirty stuff in the tank. It did start misfiring just after I had filled up at the gas station (waiting inline for the car wash at the same station, actually).
I just find it hard to believe that a dirty tank could do that and cause the exact same cylinder to misfire, but stranger things have happened.
Anyways, any input is appreciated.
It started doing it on Friday 9/3/10. It went 2 weeks without misfiring, and started back again. The frequency seems to be less, however it is throwing the P0306 code again (same cylinder as before). Since the problem started however long ago, it hasn't gone that long without misfiring. It leads me to believe that its fuel related somehow.
A friend suggested that it may be caused by a dirty fuel tank... reasoning that it ran fine for 2 weeks with a brand new fuel filter until it reached the dirty stuff in the tank. It did start misfiring just after I had filled up at the gas station (waiting inline for the car wash at the same station, actually).
I just find it hard to believe that a dirty tank could do that and cause the exact same cylinder to misfire, but stranger things have happened.
Anyways, any input is appreciated.
09-09-2010, 10:28 AM
#9
09-09-2010, 11:17 AM
#10
when you switched fuel injector with a good one and it still misfired, are you sure it was mis-firing from the SAME #6 cylinder and you just didnt transfer the problem over to a differnt cylinder?
i keep thinking you have a bad injector.
i keep thinking you have a bad injector.
09-09-2010, 11:55 AM
#11
Newbie - Just Registered
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Posts: 4
Update #2: It has started misfiring again.
It started doing it on Friday 9/3/10. It went 2 weeks without misfiring, and started back again. The frequency seems to be less, however it is throwing the P0306 code again (same cylinder as before). Since the problem started however long ago, it hasn't gone that long without misfiring. It leads me to believe that its fuel related somehow.
A friend suggested that it may be caused by a dirty fuel tank... reasoning that it ran fine for 2 weeks with a brand new fuel filter until it reached the dirty stuff in the tank. It did start misfiring just after I had filled up at the gas station (waiting inline for the car wash at the same station, actually).
I just find it hard to believe that a dirty tank could do that and cause the exact same cylinder to misfire, but stranger things have happened.
Anyways, any input is appreciated.
It started doing it on Friday 9/3/10. It went 2 weeks without misfiring, and started back again. The frequency seems to be less, however it is throwing the P0306 code again (same cylinder as before). Since the problem started however long ago, it hasn't gone that long without misfiring. It leads me to believe that its fuel related somehow.
A friend suggested that it may be caused by a dirty fuel tank... reasoning that it ran fine for 2 weeks with a brand new fuel filter until it reached the dirty stuff in the tank. It did start misfiring just after I had filled up at the gas station (waiting inline for the car wash at the same station, actually).
I just find it hard to believe that a dirty tank could do that and cause the exact same cylinder to misfire, but stranger things have happened.
Anyways, any input is appreciated.
Maybe bad ECU, i had also P0302 code and misfiring. Nothing happened on ecu pin 22 green/red wire,there were also no sparks , i wired 2 coil green/red wire from 3.coil and then there were sparks (but 60degrees late).I send ECU for repair and he said there was faulty ignition circuit. Maybe he can fix it. But it last 2-4 weeks cause Ignition circuit must order from Asia.
09-10-2010, 12:43 PM
#12
Junior Member
Join Date: Jul 2010
Location: Bogota, COL
Posts: 87
I have checked the easy stuff already:
-Purchased new OEM coil and installed on cylinder 6
-Switched out new coil from cylinder 6 with a coil from a known good cylinder
-Replaced all 6 spark plugs
-Switching spark plugs between cylinder 6 and known good cylinder
-Switched fuel injectors from cylinder 6 with a known good cylinder
-Tugged and pulled on the wiring harness from the front bank of cylinders all the way back to the firewall by the passenger side strut tower
-Sprayed starting fluid all around intake plenum, no change in idle
-Flashed ECU to updated version
I have done all of the above, and none have made any difference in the misfiring. Always on cylinder 6.
-Purchased new OEM coil and installed on cylinder 6
-Switched out new coil from cylinder 6 with a coil from a known good cylinder
-Replaced all 6 spark plugs
-Switching spark plugs between cylinder 6 and known good cylinder
-Switched fuel injectors from cylinder 6 with a known good cylinder
-Tugged and pulled on the wiring harness from the front bank of cylinders all the way back to the firewall by the passenger side strut tower
-Sprayed starting fluid all around intake plenum, no change in idle
-Flashed ECU to updated version
I have done all of the above, and none have made any difference in the misfiring. Always on cylinder 6.
I have the random misfire and because of lack of time i only checked bank 2 and found my spark plugs to be full of build up, i yet have to replace them as well as bank 1 (im sure they will be dirty too) i did not notice any oil though, is it only present on bank 1? or both? what exactly would i see if i had a leaky valve cover? my oil went so low that the dipstick did show any oil so i changed the oil and the light is still there, where does the oil go? im not getting black smoke in the exhaust...
09-14-2010, 08:50 AM
#13
The misfire has never been in another cylinder. Always P0306.
Interesting that you mention fuel. As I mentioned before, I changed the fuel filter and it didn't misfire for 2 solid weeks. Since it started misfiring, it has never gone that long without doing so (maybe 2-3 days max before). This leads me to believe that it is something fuel related.
Does anyone thing a dirty fuel filter could cause a misfire in cylinder 6? On top of that, could a new filter get dirty enough in 2 weeks to cause it to happen again?
09-14-2010, 10:09 AM
#14
Junior Member
Join Date: Jul 2010
Location: Bogota, COL
Posts: 87
It was misfiring before I changed plugs from what was in it when I bought it last year, and still misfiring after I put new plugs in. I even switched plugs with a known good cylinder after that and the misfire remains in cylinder 6.
The misfire has never been in another cylinder. Always P0306.
Interesting that you mention fuel. As I mentioned before, I changed the fuel filter and it didn't misfire for 2 solid weeks. Since it started misfiring, it has never gone that long without doing so (maybe 2-3 days max before). This leads me to believe that it is something fuel related.
Does anyone thing a dirty fuel filter could cause a misfire in cylinder 6? On top of that, could a new filter get dirty enough in 2 weeks to cause it to happen again?
The misfire has never been in another cylinder. Always P0306.
Interesting that you mention fuel. As I mentioned before, I changed the fuel filter and it didn't misfire for 2 solid weeks. Since it started misfiring, it has never gone that long without doing so (maybe 2-3 days max before). This leads me to believe that it is something fuel related.
Does anyone thing a dirty fuel filter could cause a misfire in cylinder 6? On top of that, could a new filter get dirty enough in 2 weeks to cause it to happen again?
FYI- i put seafoam in the tank and the engine oil and drove for about 100+ miles, sometimes hard, sometimes easy and my SES light went away, although i still have the symptoms, i will be replacing the spark plugs once the tank of gas is gone and will post back with results
09-14-2010, 10:16 AM
#15
just another idea, did you check your O2 sensor 1? i assume you dont have consult II so take a look at the FSM page EC-321 if you haven't already. for my case i ran the troubleshooting procedure up to step 6 and found crapped out spark plugs, so ill take it from there.
FYI- i put seafoam in the tank and the engine oil and drove for about 100+ miles, sometimes hard, sometimes easy and my SES light went away, although i still have the symptoms, i will be replacing the spark plugs once the tank of gas is gone and will post back with results
FYI- i put seafoam in the tank and the engine oil and drove for about 100+ miles, sometimes hard, sometimes easy and my SES light went away, although i still have the symptoms, i will be replacing the spark plugs once the tank of gas is gone and will post back with results
I have tried SeaFoam in the tank as well as some BK44 to no avail. Never tried it in the oil. I cant remember if I replaced the spark plugs after the Seafoam or before....
09-17-2010, 09:34 AM
#16
Junior Member
Join Date: Jul 2010
Location: Bogota, COL
Posts: 87
I am not familiar with that FSM, but I have recently replaced both O2 sensors on Bank 2 (front), and the post-cat O2 sensor on Bank 1(rear). I have the last O2 sensor but haven't put it in yet, but Bank 1 shouldn't have any effect on this misfire issue.
I have tried SeaFoam in the tank as well as some BK44 to no avail. Never tried it in the oil. I cant remember if I replaced the spark plugs after the Seafoam or before....
I have tried SeaFoam in the tank as well as some BK44 to no avail. Never tried it in the oil. I cant remember if I replaced the spark plugs after the Seafoam or before....
so like i said, wait till i get the plugs replaced and will post back
Last edited by silver5andahalf; 09-17-2010 at 09:36 AM.
09-18-2010, 04:27 AM
#18
Junior Member
Join Date: Jul 2010
Location: Bogota, COL
Posts: 87
but city driving makes it come back
09-30-2010, 01:50 PM
#22
09-30-2010, 03:53 PM
#25
could be so, I'm far from being a professional with the maximas. I just figured if six went out the others can't be far behind and if one of the coils is working intermittently then it might not show that code. I am a noob so im shuting up lol
10-01-2010, 06:50 AM
#26
Senior Member
Join Date: Mar 2004
Posts: 497
Given that you have switched coil, plug and injector but the misfire stays with cylinder 6, it looks like it is either wiring issue or mechanical (i.e. valve, head-gasket etc). Can you trace primary ignition wire and injector wire loom all the way to the ECM? Possibility of wire getting chafed and losing its insulation is lot higher than ECM going faulty. If you have lead good life (i.e. changed oil at reasonable interval) there is no reason you would have mechanical issues.
Good luck!
- Vikas
Good luck!
- Vikas
10-04-2010, 04:21 AM
#27
Junior Member
Join Date: Jul 2010
Location: Bogota, COL
Posts: 87
but i still have a P0011 code, i dont know what else to do, i cleaned the solenoid, checked all cables... :sigh: but no more missfire and the car feels a little more powerful 
This is one of the plugs before anything was done: http://forums.maxima.org/album.php?a...ictureid=21260
This is a new plug: http://forums.maxima.org/album.php?a...ictureid=21261
Last edited by silver5andahalf; 04-07-2011 at 06:56 AM. Reason: typo
10-29-2010, 11:10 PM
#28
Newbie - Just Registered
Join Date: Oct 2010
Posts: 1
Hi guys, I'm a ASE certified tech. I had a customer with the same problem. It was a #3 cylinder misfire. I did the switch thing also , to no avail. Thanks to my Snap-on SOLUS PRO wisdom I told my customer I needed to replace all the coils. I even showed her the code trouble shooter info on my scanner. She agreed to replace all the coils. Misfire gone. However I created another problem. Now I have a P1320 code because I tried to save her some money and bought them at Napa. Replace all 6 coils with OEM parts and you'll thank me later. I promise.
11-17-2010, 06:22 PM
#30
Don't mean to sound redundant but when 1 coil goes, you might as well replace all 6, had the problem for months where 3 cylinders threw codes after replacing all plugs, harnesses, ecu flash, and 3 new oem coils. Only went away when I replaced the remaining 3 coils.
I know it could be pricey and very annoying, by I suggest replacing the rest of the coils.
I know it could be pricey and very annoying, by I suggest replacing the rest of the coils.
04-05-2011, 07:34 PM
#31
Alright, I am bringing this thread back to life because I still have the misfiring.
I replaced the ECU with a reman unit from the dealership and had them install and reconfigure everything. (I did this as I pulled my then current ECU out and it was clear that water had gotten into the unit and there was corrosion on the board plus my buddy the Nissan tech is usually spot on.) Didn't misfire for a day, but its back with vengeance now.
Since the posts above, I replaced the spark plugs again with OEMs (had Auotlites before), and today I switched coils between the bad 6th cylinder and a good cylinder (2), and it still continues to misfire and throw a P0306.
I just don't understand why it would not misfire for 2 straight weeks when I replaced the fuel filter/strainer and then come back. Could it have something to do with fuel pressure? I mean, replacing the fuel filter/strainer does mess with the fuel pressure since you have to disconnect the lines and pull the fuse? I may be wrong, I am no mechanic...
What's next? Switch out the injector again? I am second-guessing everything I have done now...
I replaced the ECU with a reman unit from the dealership and had them install and reconfigure everything. (I did this as I pulled my then current ECU out and it was clear that water had gotten into the unit and there was corrosion on the board plus my buddy the Nissan tech is usually spot on.) Didn't misfire for a day, but its back with vengeance now.
Since the posts above, I replaced the spark plugs again with OEMs (had Auotlites before), and today I switched coils between the bad 6th cylinder and a good cylinder (2), and it still continues to misfire and throw a P0306.
I just don't understand why it would not misfire for 2 straight weeks when I replaced the fuel filter/strainer and then come back. Could it have something to do with fuel pressure? I mean, replacing the fuel filter/strainer does mess with the fuel pressure since you have to disconnect the lines and pull the fuse? I may be wrong, I am no mechanic...
What's next? Switch out the injector again? I am second-guessing everything I have done now...
04-06-2011, 07:17 AM
#33
04-06-2011, 03:22 PM
#35
this may sound dumb but ive had a misfire plagued me for about a week n a half after installing my headers... turns out its one of my o2 sensor wires was loose... my question to you is if you pass a certain RPM does the misfire go away???
04-06-2011, 03:45 PM
#37
Question, when you change your spark plugs do you see oil on them? If so, you may need to change your valve cover gasket and spark plug cylinder seals. Also stop wasting money on coil packs. Get a test light and see if your getting power from that coil period. If you're not getting power from that coil, check your wiring, by getting a multimeter, and checking the wires for volts and also resistance. If resistance is low the wiring for that coil may be corroded. Which can cause the coilpack to not get enough juice to power it fully, or you may not be getting power to it at all.
04-07-2011, 05:47 AM
#39
Question, when you change your spark plugs do you see oil on them? If so, you may need to change your valve cover gasket and spark plug cylinder seals. Also stop wasting money on coil packs. Get a test light and see if your getting power from that coil period. If you're not getting power from that coil, check your wiring, by getting a multimeter, and checking the wires for volts and also resistance. If resistance is low the wiring for that coil may be corroded. Which can cause the coilpack to not get enough juice to power it fully, or you may not be getting power to it at all.
I have thought the exact same thing but why would it only cause a misfire in cylinder 6?
04-07-2011, 07:39 PM
#40
I haven't checked it with a scope, but the misfire occurs when the engine is cold and hot, low RPM, high RPM... which leads me to believe its not carbon build-up. I am not ruling it out, but I was under the impression if it were carbon build up, it would get better once the engine got hot, right?