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Old 01-18-2013, 09:39 AM   #1
sorrowfulkiller
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Default strange misfire....

On my girlfriends car, a 98 subaru legacy gt with a dohc 2.5l, its got a cylinder 2 misfire. So I did the usual, plugs, wires, ignition coil, front O2 sensor and some fuel injector cleaner. No change at all.

The car has 160k miles on it, headgaskets both done at 155k miles, both valve cover gaskets have been changed. Basically the car should be in great shape. Fuel filter was even replaced about 4k miles ago. I'm at a loss.
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Old 01-18-2013, 10:58 AM   #2
Patrick Olsen
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Years ago, on my then stock '97 2.5GT, I had a misfire on #2 that turned out to be a burned exhaust valve. A problem with plug wire or plug is much more common, but since you've already done all the "normal" stuff, it could be something mechanical.



That was at 50-something thousand miles, so it's certainly not hard to imagine that the same sort of thing could happen on an engine with 3x as much mileage.

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Old 01-18-2013, 12:12 PM   #3
chickennecks?
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I'm in the exact same boat. So what exactly causes a burnt valve, and what's the fix?
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Old 01-18-2013, 04:59 PM   #4
sorrowfulkiller
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Say it isn't so! Eh oh well. She can drive it til it breaks.
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Old 01-20-2013, 11:15 PM   #5
myslowgrandmacar
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I am also currently having misfire issues. I am already in the process of changing out all the usual culprits but I am going to have a hard time troubleshooting because it's not something that is happening on a consistent basis. Hoping it is not the worse case which is valve issues.
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Old 01-20-2013, 11:18 PM   #6
boostjuice
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Grounding kit? Heard it helps with this type of stuff - Im getting random misfires as well and the Grounding Kit is next on my list
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Old 01-21-2013, 09:59 AM   #7
monkeyposeur
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Have you checked the resistance of your fuel injectors with a multimeter? Should be 11-12 iirc.
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Old 01-26-2013, 01:26 PM   #8
Charlie-III
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When does the misfire happen? Under load, coasting, warm out/cold out, wet out/dry out?

Also check the intake manifold bolts, they can loosen up a bit.
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Old 01-26-2013, 01:34 PM   #9
sorrowfulkiller
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Quote:
Originally Posted by Charlie-III View Post
When does the misfire happen? Under load, coasting, warm out/cold out, wet out/dry out?

Also check the intake manifold bolts, they can loosen up a bit.
misfire happens at low load and idle situations only. Under high load all i well.



I'll have to check into injector resistance.
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