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Discussion Starter #1
So I have a random misfire that only occurs at start up. After 30 seconds it is gone for the rest of the day. I replaced all the plugs and coils but to make a long story short after a while I determined it is the crank sensor. So i got another which did fix the issue for about a week. I got another one and just figured the part was defective So misfire happened again consequently I went to a different parts store and got another camshaft position sensor. Same thing happening again. Although the car is perfectly drivable I dont want this to escalate to something else and have some ghost in the machine unfixable issue. It Misfires for 15-30 seconds then smooths out to normal and is good till tomorrow morning. I think it is extremely rare to have 4 bad parts in a row and Im guessing something else must be causing the issue and Before I drop 150 on the Nissan branded part I want to make damn sure its not something else causing the camsensor to fail upon startup.

So the only backgroud I have to this story ~ all these misfires began after I attempted to advance timing 2* with the Nissan datascan tool. I was just messing around and wanted to see what difference it might make if any. Well I did "feel" a little stronger but after a couple of days the cel came on and ALSO i NOTICED MY mpg WENT WAY DOWN. So I changed it back to where it was before but the CEL keeps doing its thing with the cold start misfires.

Anyone know anything about this or have any ideas?
 

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When was the last time you changed/gaped the plugs, a little silly but ecu could be comparing on child start up or it's the head gasket?
 
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Discussion Starter #4
had a misfire last night coming home from work. CEL came back on code 0300 random misfire. Once at the house it would not restart right away, but after cooling down it did restart but with an awful misfire. So this morning I had the crankshaft position sensor replaced under warranty. This is the lifetime warranty part from O'reilly's. So this is number 5 i think. 2 from Advanced and 2 from Oreilly's and the original was the one I got from 2J Racing. The lifetime one is manufactured by Standard. I have had good experience with them in the past...With the new CPS starts up like new and no misfire...cel doesnt come on. They have been lasting about a month so...
If this fails Ill get the Hitachi ....
Ill keep you guys posted so we know what works and what doesnt.
 
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on another note, you should NOT advance timing on a boosted engine, unless you know what you are doing, and do so in the tune itself. very bad things can happen with just a couple of degrees.
 

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on another note, you should NOT advance timing on a boosted engine, unless you know what you are doing, and do so in the tune itself. very bad things can happen with just a couple of degrees.
Don't I know this all too well...
Hahaha
If anything, add a pound of boost and pull a degree or so of timing to add extra power...

Sent from my XT1028 using Tapatalk
 

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Also want to make a note here too

When it comes to the crank and cam sensors, I always change both! When one goes, it's been my experience that the other is not far behind...

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and thats why you keep two new ones!!!
Yup, when I changed out the last pair not to long ago I replaced them!
I have a new pair sitting on the spare parts shelf.

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What year is the car
What are you using to tune the car
What code did it throw?
First.... You should be pulling 2 degrees not adding 2 degrees of timing....
It always the same cylinder? Have swap the coils around??
If it only does this on startup I would let the car sit, pull the plugs and check to make sure it's not a leaky HG.
 

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Discussion Starter #12
Well crickikaze I think youre a genius bro. I didnt think that the gap could possibly be the culprit, since I had replaced the plugs some time ago and left them at the factory spec. There was a time when at WOT I would get misfire and shortened the gap to 0.038 which fixed that, but after installing new plugs I left them at factory spec just to see. And I suffered no WOT issues so I left them as is. But the cold start misfire came out of nowhere. However after the 5th crank sensor and only other option left was the OE brand....I decided to troubleshoot any and all ideas starting with your idea and shorten the gap again. 2 days and multiple cold starts and not one misfire...no misfires at all. Thanks for the good info brother!

If it acts up again Ill post....cause I hate reading through threads about an issue online where the thread just ends and I never know ~ did it get fixed or not? what actually happened? so ill keep everyone posted.
 
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