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Guest Message by DevFuse
 

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99 Impreza OBS 2.2 PO304, Miss fire on #4 Cylinder


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6 replies to this topic

#1 lmdew

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Posted 11 February 2013 - 08:14 PM

The Daughters OBS was running a little rough off idle the last time she was down.  Now she has a miss fire on #4.  I did do Seafoam in the Intake and a Lucas Gas Treatment in the Tank the last time she was down.  Plugs have been changed to NGK copper core.  Going to have the #1 son swap the plug wires side to side and see if the fault follows.  

 

If an injector was leaking the plug would be fouled.  I have not seen the plugs, so hard to tell.

 

Valve Cover gaskets and the Spark plug tube seals were changed about a year ago. 

 

140+ K miles.

 

Other ideas?

 

Thanks, Larry



#2 ShawnW

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Posted 11 February 2013 - 08:22 PM

Has she had anybody other than you or your son work on it?  



#3 lmdew

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Posted 11 February 2013 - 08:23 PM

No



#4 lmdew

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Posted 12 February 2013 - 05:29 PM

I'm away from my garage, is the valve clearance set with the screw and jam nut on the 99 2.2.  

 

Thinking the valve may be slightly open.  I did clean the system with seafoam and lucas fuel system cleaner.  Could have cleaned the carbon off the valves?

 

Larry



#5 Fairtax4me

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Posted 12 February 2013 - 05:52 PM

Yes, lash clearance is adjustable with a screw on the rocker. Wouldn't think valve clearance should be an issue, but if they've never been adjusted its possible.

#6 lmdew

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Posted 14 February 2013 - 11:45 PM

Coil was corroded on 2 of the 4 terminals.  Swapped the Coil and plug wires, new NGK copper core plugs and it's operating on all 4 cylinders again but still stumbles when you have 25-50% throttle in.  No codes but the plugs are very rich. 

 

Going to check the TPS, MAF, O2 and Knock sensor.



#7 lmdew

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Posted 17 February 2013 - 07:21 PM

Son had another coil from his buddy's car.  4 pin connector.  It started running on all 4 but then would not rev above 2500.  Very Strange.  I went up today, bolted on a use Subaru Coil I had, Problem Solved.  Lessons learned, Only use Subaru Coils and NGK or Subaru Plug wires.

 

Back on the road.  Thanks Larry






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