# multi misfire need help



## bug2110 (Jun 17, 2010)

So I went out to my car this morning after not starting it for two days. Start it up running like shit went inside to get scan tool come back cars running fine tool says multi clinder misfire. That was the only time its done that. I've notced that other time if you don't warm it up b4 driving it will misfire when you give it gas. But never this bad. Also burns some oil worse when on high way. Things to note has aftermarket header. 3 inch cold air intake and cat baack exhaust. Any ideas. I'm thinkin might be bad head gasket. But clinder presser test says all clinders are in normal range. Oil looks good not :wtf:milkey. Same with coolent.


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## bug2110 (Jun 17, 2010)

O ya cars a 2003 nissan sentea se-r spec v. Qr25de engine.


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## bug2110 (Jun 17, 2010)

also just to add i heard the car is not burning oil cuz theirs never white or blue smoke.(so dont know where the oils going) i do have a lot of black soot. and if you drive it hard black smoke comes out at the higher rpms. i taught that was burning oil but someone told me thats the engine running rich. guess thats another problem to add to the list.:balls:


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## SPEEDO (Jun 9, 2003)

might check your plugs... I'll bet you have a head gskt going


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## bug2110 (Jun 17, 2010)

Ya ill check them also would bad head gasket cause power to be shitty before 3000 rpms? Friend has same car has a lot more power b4 3000 rpms. All he has is a cat back so I would think mine should have more power out of the hole.


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## SPEEDO (Jun 9, 2003)

have the screws for butterfly valves been locktited?
if your head gskt is going, coolant will seep into the cylinder and may cause a misfire until it gets burned out... maybe you have more coolant seeping into the cylinder than can be cleared out... causing a constant misfire


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## bug2110 (Jun 17, 2010)

also just tried to compare the amount of air coming out of my exhaust to my friends spec v to see if my secondary cat was clogged when my friend put his hand back their it covered it in this brown shit looked like flakes said was not slimy just wet? what could that be. 

i also test drove his car today at low rpms his pulls much harder than mine, but at higher rpms my pulls harder what could that mean he has about same miles no oil problems and stock intake and 3 inch catback exhaust with stock cat header.
i would think our power should be close to the same i would not think i would loose that much low end from just headers and a 3 inch cold air intake and a megan catback.

thanks sorry about the long explanation


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## SPEEDO (Jun 9, 2003)

when you open up the exhaust (bigger pipe) you will loose some" back pressure" which is what gives you low end power, but with the larger pipe the upper end will perform better... so you have to find a balance... loose a little/gain a little


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