# S4 rundom misfires



## maciekb2002 (Oct 24, 2008)

Just picked up an S4 ,
It has misfires. Checked for vacuum leaks. none
You can hear misfires while car is idling and also while driving
But they are very irregular. Car spools up very quick.
Didn't feel misfires on the load. CEL comes on. 
Car has tons of modifications 
RS4 interoolers , K04 turbos with non OEM manifolds, intercooler piping
Tune by Giac, 3.5'' maf 
It shut off on me ones while idling, engine hot
Doesn't miss when is cold.
Didn't drive it on a highway yet but feels like 400 whp car.
If you can give me an idea? 
Didn't check compression yet.
coils?
igniters?
Plugs? I say no 
Thanks


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## maciekb2002 (Oct 24, 2008)

no help , there has to be somebody here who had similar issues


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## nikitynick (Jan 14, 2007)

*Re: (maciekb2002)*

check your coilpacks, spark plugs, any codes


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## green 25 (Jun 26, 2008)

if only 1 cylinder has a misfire change that coil pack to another cylinder and see if the misfire follows to that cylinder ......if it follows the problem is the coil pack ..........good luck


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## -mlfhntr- (Jul 18, 2007)

Well, my friend had a random misfire on a S4 he picked up a couple of months ago. Had a random Limp mode that would accompany the misfiring. Found that one of the valve gaskets was leaking oil down around the plugs. Best thing is to pull codes that is what we did.


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## jettasmooth (Aug 7, 2002)

check what code is coming up, see if its always on one particular cylinder or a particular bank of cylinders. If you switch the wiring to the power output stage for each bank of coilpacks, and the CEL code switches to the other bank, you will know that the power output stage is faulty. They are located on top of the intake on early S4's and A6 2.7T


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