Single cyl misfire?

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Sep 23, 2010 | 10:24 AM

Daremo_06

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From: Rhode Island

Single cyl misfire?

What can cause a single cylinder to repeatedly misfire? Coil pack? wiring harness? Problem is, car starts on 6 cyl then drops out #5 after a few minutes. I dont have codes currently, I will later.

If it was improperly adjusted cam adjuster during timing belt install, that would problems across the whole bank right? This problem is localized to #5 only.

Thoughts?

Sep 23, 2010 | 11:21 AM

jschick

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From: N.E. Ohio

could be many things, plug, wires coil, fuel injector, bent valve, or sticking valve, or out of time. depending on which way, how much and what, is out of time it could be possible to only affect 1 cyl. I know that if the cam is out of time it will affect the whole bank, but it is possible that since the lobes are egg shaped it could only have "major" effect on 1 cyl.
but you can start by swaping coils, and plugs an hope it's something simple

Sep 23, 2010 | 02:11 PM

e292644

Audiworld Junior Member

Joined: Jun 2010

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From: SoCal

I got almost the same symptom like yours. Cylinder #5 misfire, no error code.
Spray some soap+water over your coil and wires then start the engine.
Better do this during the night. You may see some spark dancing if you are lucky. Most likely it's your wires.
I replaced whole wire set and it went away.

Sep 23, 2010 | 03:53 PM

Peter Badore

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Quote:

Originally Posted by Daremo_06

Add a possible broken valve spring.

Sep 23, 2010 | 06:47 PM

Zaphodb17

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Quote:

Originally Posted by Daremo_06

Make sure there is no vacuum leak associated with the #5 cylinder, that comes into play after warm-up. Cold enrichment masks alot of normal temp running problems. Search for a vacuum leak in the #5 intake runner or intake gasket to disqualify that as an issue. Having said that, usually something like this is a plug wire problem as "e292644" said. G'luck

Sep 24, 2010 | 05:21 AM

massboykie

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Joined: Feb 2006

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From: Natick, MA

Quote:

Originally Posted by Zaphodb17

... Having said that, usually something like this is a plug wire problem as "e292644" said. G'luck

Yeah, I agree and would suggest starting with the easy stuff...

I also think a cam timing issue will cause problems on the whole back, probably not the one cyl. I would start by swapping the plug with another. Then the coil and if still there the ignition control module on the air box. You can swap the wires between the two units.

One more question though... if you have scanend the car, how do you know it is cyl 5 misfiring?

Cheers
Massboykie