# random misfires



## improvleo (Sep 3, 2010)

repair shop could not fix this. having random misfires every couple of minutes, replaced coil pack, injectors, wires, plugs, fuel filter, drained tank found bad gas, and re flashed the ecm. car drives fine 90%of the time. i think its fuel related possible fuel pump or pressure regulator any ideas?


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## O_o (Nov 12, 2009)

What are the codes?


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## tryin2vw (Dec 30, 2006)

As  says, what are the codes. Could be a vacuum leak, could be the MAF, could be spark plugs due to clogged PCV.....


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## improvleo (Sep 3, 2010)

P0300, p0301,p0302, p0303, p0305, p0306 maf was checked an tested ok. Car don't idle rough it just stalls pcv checked ok just found crushed vac line going to front and other lines are cracked so changing them now.


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## improvleo (Sep 3, 2010)

vac lines replaced still stalls at random only thing left is fuel pump.


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## O_o (Nov 12, 2009)

I'd check the fuel pressure before just throwing a new pump at it. There are still plenty of other things it could be, such as the FPR, EGR valve, exhaust constipation, etc... It's especially odd that you only have misfire codes. The O2 sensors should complain if the AFR is off, so it's seems to me more likely you have a wiring problem in the ignition system. That would also throw one or more codes, but possibly not a generic P-code your scanner understands.

Also: how's your compression?


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## tryin2vw (Dec 30, 2006)

Only cyl 4 is not misfiring, so that could be a clue. Check the wiring from the coil to each spark plug.


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## improvleo (Sep 3, 2010)

compression is good. having trouble starting just dosnt want to start but if i get it running i can usualy keep it running with the misfires but its got me going crazy


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## O_o (Nov 12, 2009)

Does it misfire all the time, or only at idle? Does it start easier if you give 'er some gas? Have you tried spraying ether in the intake?


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## improvleo (Sep 3, 2010)

it dosnt misfire all the time sometimes it starts right up and sometimes only one cylinder will misfire then theirs times it misfires multiple cylinders. it runs smooth as silk 90% of the time


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## O_o (Nov 12, 2009)

OK, but when it is misfiring, is it only at idle?


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## improvleo (Sep 3, 2010)

it misfires at dile an all the way up to 500 rpm or more


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## improvleo (Sep 3, 2010)

i think im leaning towards the vac lines still lines are new but thatch the only thing. how would i go about troubleshooting solenoids and pumps


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## O_o (Nov 12, 2009)

Um... you mean 5,000 rpm? That would have to be one hell of a huge vacuum leak. The O2 sensors would be complaining loudly too, and it doesn't make sense that it would be intermittent. My money's still on the ignition circuit wiring. See if you can find somebody in your area with a VAG-COM. It will read all kinds of additional codes that generic scanners don't understand.


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## improvleo (Sep 3, 2010)

i will see what i can find finaly got ot to idle for 40 minutes before it stalled


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