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Discussion Starter #1
A couple weeks ago, my check engine light was on. So I took the OBDII reader and found that my EGR valve was acting up. A week later the check engine light turned off but felt my outback misfire (Still till this day). Does the EGR valve make your engine misfire?
 

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2001 VDC/SC One of a Kind
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Not usually. Normally, there are no drive-ability issues at all with an EGR fault. I could see it if the EGR valve was stuck in the open position, but that would be highly unusual.
Stuck open means a vacuum leak at idle and it will run rough or die. Misfiring at idle only or during acceleration from a stop.

Not opening when the ECM wants to run the EGR will not cause an issue, neither if its stuck open and you are cruising.

When the EGR runs, the ECM is looking for a change in the MAP sensor data as well as a change in the Transducer pressure. It opens the EGR in degree variations during cruising where the "leak" won't cause and issue with performance.

Misfiring could be timing, spark, fuel or vacuum leak.
 

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Discussion Starter #4
Past Codes

I changed the spark plugs at the beginning of Jan. because I ran a P0304. I have a check engine light on again and ran a P0440. But I still do not know why my engine is misfiring. Could it be an injector?
 

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Car: 2008 Tribeca, 2010 LGT, Sold: 2005 XT Limited
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P0440 is your gas cap, not a misfire.
 

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Discussion Starter #6
I know that..... I opened and closed the gas cap today..... But the engine "stumbles" while it accelerates and idles. Cardoc, could you expand on this issue?
 

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2001 VDC/SC One of a Kind
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What year is your car?

With data, yes. Otherwise I can only give you things to look for.

P0440 is a general EVAP code. Could be a gas cap issue, either not on tight or its bad. Could also be a vacuum leak. Which would also cause a misfire.

Check the vacuum hose that connects at the fuel rail assembly in the same place the fuel lines connect. It will be the smaller of the hoses. Check for any cracks in the hose between the fuel rail and where it connects to the steel line going back to the tank. Sometimes this hose will crack creating 2 separate issues.

Depending on the year, other things to check are fuel delivery, battery, grounds, alternator, PCV valve, throttle body condition and a few more.
 

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Discussion Starter #8
Ok
So technically it could be either EGR or EVAP. RIght? I am going to clean the EGR first next week because Storm Nemo is coming my way. If that doesn't work then I'll examine the hoses and what not.
 
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