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Big misfire problem, please help!!

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Old Jan 12, 2005 | 06:23 PM
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Default Big misfire problem, please help!!

Hey guys, hows everyone doing? I recently come upon a bad misfire problem. It happened out of no where while I was driving down the road. Ive tried swapping coil packs, plugs, and wires and the misfire doesnt seem to follow. Autotap says its misfiring in cylinders 5 and 7, but it sounds like I have a vaccum leak somewhere that I cant find.

Also, while I was tryin to fix that problem, the car was sitting at idle and the exhaust valve spring broke on the number 8 cylinder. I replaced the spring, the pushrod, and the rocker arm there since the bearings on that blew out. For some reason, that rocker arm wont get tight, it still woobles with the stud torqued down. Does anyone know why that is?

As for the misfire itself, its gotten to late in the day to pop open the other valve cover, but it sounds more like a vaccum leak then something wrong under the driver side valve cover, but i could be wrong. I can hear hissing but cant find the leak. Then again I dont really know where the vaccum lines run. Anyone have an advice or know where I should look next to solve my problems?
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Old Jan 12, 2005 | 07:22 PM
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oh yea, forgot to tell you guys, ever since Ive replaced the spring pushrod and rocker, I can only get one dtc code, p0101, mass or volume air flow performance problem. I dunno what is causin that. Also, that exhaust valve the has the new spring doesnt seem to be sitting as high as the over valve, does this sound like a bent valve?
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Old Jan 12, 2005 | 11:45 PM
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did you lap the valve when you changed it out? that may be one problem as to why the valve doesn't sit all the way in the seat. I had a random misfire end up being broke pushrod. Could no's 5 and 7 be bent? I'd pull the valve covers and check.

Nate
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Old Jan 13, 2005 | 12:11 PM
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ttt please
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Old Jan 14, 2005 | 12:59 AM
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oh yea, what do you mean by "laping the valve" anyway?
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