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Engine missfiring, oil on spark plug electrode 99' A6 2.8L

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Old Apr 7, 2009 | 02:55 PM
  #11  
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He means in the compustion chamber.. Needs to verify spark before doing anyhting else.
 
Old Apr 7, 2009 | 09:45 PM
  #12  
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I dropped it at the shop and was told the injector is bad, but somehow I don't see how this would cause oil buildup on the spark plug. So I took it back home and will try replacing the valve cover gasket next.
 
Old Apr 9, 2009 | 03:47 PM
  #13  
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So I just found that the breather hose was split in two right below the cylinder shaped thingy that plugs into the suction pump. I wonder if that was the cause of my leaks due to pressure buildup. Replaced the entire breather hose with 3/4 heater hose as it had small cracks all over, but engine still misfires.
 
Old Apr 9, 2009 | 04:16 PM
  #14  
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Very well could be part of the problem with the amount of oil you observed on the plug. With out the vaccum, pressure will push oil past the rings into the compustion chamber. Dont think it was the main cause, however. What was the result of the spark test?
 
Old Apr 9, 2009 | 08:46 PM
  #15  
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Originally Posted by Midniteoyl
Very well could be part of the problem with the amount of oil you observed on the plug. With out the vaccum, pressure will push oil past the rings into the compustion chamber. Dont think it was the main cause, however. What was the result of the spark test?
Spark is good.
 
Old Nov 3, 2009 | 10:22 PM
  #16  
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I'm having the exact same problem with my '98 A4 2.8, Took it to Audi and they replaced the seals on the cam tensioner and valve cover gasket, they also replaced the breather hose, it is still leaking oil into the cylinders and causing misfires. I read on another forum that it may be the piston rings have worn out. However, in the short term I'm using a fuel additive that raises the octane and cleans the combustion chambers so it only misfires when it's at a stop sign or stop light now (without the fuel additive it has RPM wavering and loss of power due to misfiring on almost all cylinders). Any other Ideas on this?
 
Old Nov 3, 2009 | 11:16 PM
  #17  
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Originally Posted by indie.ianjones
I'm having the exact same problem with my '98 A4 2.8, Took it to Audi and they replaced the seals on the cam tensioner and valve cover gasket, they also replaced the breather hose, it is still leaking oil into the cylinders and causing misfires. I read on another forum that it may be the piston rings have worn out. However, in the short term I'm using a fuel additive that raises the octane and cleans the combustion chambers so it only misfires when it's at a stop sign or stop light now (without the fuel additive it has RPM wavering and loss of power due to misfiring on almost all cylinders). Any other Ideas on this?
It ended up being a bad fuel injector on one of the cylinders.
 
Old Nov 4, 2009 | 01:16 PM
  #18  
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Default 98 a6 2.8 q

just pulled apart mine due to doing timing belt circus and decided to pull off and do the valve cover gaskes. had oil all over and in the same plug and it surley looks like the gasket was bad all around that area ........hope that helps.
 
Old Nov 4, 2009 | 09:43 PM
  #19  
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The valve stem seals may be replaced without removing the cylinder heads by using compressed air through the sparkplug hole to keep the valves in place.
You could also get oil leaking in to the combustion chamber from a bad head gasket, a cracked cylinder head, etc.
A weak spark may cause the sparkplug to foul, so check your ignition.
A MSD multiple spark ignition may keep the plug from fouling, however it is rather expensive and may require special sparkplug wires and coils.
 
Old Nov 5, 2009 | 11:34 AM
  #20  
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the oil is pooling in the spark plug wells, could a bad spark or injector cause this?
 
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