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Old 06-21-2009, 12:42 AM   #1
Aleksey
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Default Misfire cyl#4 ONLY on cold engine

Not just another "I got misfire, what do I do" thread, so read on

Yeah, I got cyl #4 misfire and I'm gonna do the coil swap, sparkplug swap, check grounding etc, but before I start messing with it I just wanted to see if anyone had it the same way I do:

I get P0304 about once a week regardles of the ambient temperature or milage driven. I get it within a minute or two after I start the car so the engine is relatively cold. It doesn't matter if I leave the car idling, if I rev the engine a few times or if I just drive away without letting it idle for a bit - if the code pops up, it pops up no matter what I do. But as I said, the code pops up about once a week, give or take a day or two.

Due to this special behaviour I thought I'd see if anybody had some extra thought on this issue. Thanks in advance.

P.S. The car is a daily driver and almost stock - APv2 Stage 2 and COBB downpipe are the only mods.
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Old 06-21-2009, 10:02 AM   #2
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i wouldnt consider a downpipe and stage 2 reflash to be almost stock first of all. But your on the right path by changing out spark plugs and coil, maybe run some injector cleaner as well. Do a compression check since you're already removing the spark plug. Seems like the standard procedure for a misfire, ill be doing it this week as well
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Old 06-21-2009, 11:08 AM   #3
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^ compression check.
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Old 06-21-2009, 01:34 PM   #4
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Frankly, before I did anything else I'd swap injectors first and see if the CEL moves. So many of these odd misfires are injector related, that should be at the very top of the checklist. Just my $0.02.
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Old 06-21-2009, 02:18 PM   #5
sense of nature
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Maybe a sticking valve ? Too tight of valve clearance
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Old 06-21-2009, 02:29 PM   #6
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Quote:
Originally Posted by sense of nature View Post
Maybe a sticking valve ? Too tight of valve clearance
yeah, after searching NASIOC on this issue and added this to the check list too.
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Old 06-21-2009, 02:30 PM   #7
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Just wondering, is there a software I could use to automatically snapshot all the OBDII data when a code pops up? I don't think ECUExplorer has this feature, does it? I'll also ask in the proper forum, but just throwing in the idea - after searching around I don't think anyone mentioned this as another way to narrow down the problem cause.
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Old 06-21-2009, 04:50 PM   #8
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The ROM Raider logger is pretty good. If you have an access port, you could use the AccessTuner RACE logger too. The engine roughness monitor value is available in both. I run a twin disk clutch and ended up needing to adjust the misfire detection sensitivity in the ECU to get my CEL to go away.

While our issues are surely different, you should read this thread and try the same things that I tried in an attempt to solve your issue.

http://www.iwsti.com/forums/2-5-lite...-misfires.html
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Old 06-22-2009, 02:32 PM   #9
SimonJ
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Start with the basics

1) Swap coils
2) Swap plugs
3) Swap injectors

Then, and only then should you start with the more complicated diagnosis.
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Old 06-22-2009, 06:42 PM   #10
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Quote:
Originally Posted by SimonJ View Post
Start with the basics

1) Swap coils
2) Swap plugs
3) Swap injectors

Then, and only then should you start with the more complicated diagnosis.
While you're swapping the plugs, do a compression test.
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Old 06-23-2009, 01:54 AM   #11
Aleksey
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Thanks everybody for your replies. I'll update once I have results.
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Old 06-23-2009, 02:00 AM   #12
Aleksey
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Quote:
Originally Posted by dexterous View Post
The ROM Raider logger is pretty good. If you have an access port, you could use the AccessTuner RACE logger too. The engine roughness monitor value is available in both. I run a twin disk clutch and ended up needing to adjust the misfire detection sensitivity in the ECU to get my CEL to go away.

While our issues are surely different, you should read this thread and try the same things that I tried in an attempt to solve your issue.

http://www.iwsti.com/forums/2-5-lite...-misfires.html
That was interesting thread to read, glad you sorted this out. I haven't played with ROM Raider before, will download and check it out too. Thanks!
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