2005 low idle misfire po301

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Kevin Anthony

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Philadelphia
Ram Year
2005
Engine
Hemi 5.7
Hi guys,

Brand new to the forums here. Right off the bat here I should say that I am not mechanically knowledgeable but I have a couple of buddies who are and have been trying to help me with this issue. I just bought a 2005 ram 5.7 SLT 4x4 about 2 months ago. Here is what's happening:
- misfire code po301
- the only noticeable thing other than the check engine light being on, is that it idles slightly rough
- changed the spark plug wires, plugs and new fuel pump
- my friend swapped out the fuel injector with 1 and 3 to see if the code follows, and it did not.
- it still has really good power and anything out of idle position it seems to run great.
- you can definitely tell there is a misfire at idle though, just slightly rough, but once I start going it runs strong.

Were having a hard time figuring it out. I really want to get it fixed but just not sure what direction to go in. Any help and knowledge would be greatly appreciated.
 
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Kevin Anthony

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2005
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My friend did it for me so I'm not totally sure, but I think he said everything looked fine
 
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Kevin Anthony

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Also, there's no ticking sound that might indicate a broken valve spring (from what I am learning)
 

Oliver Closehauf

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2005 Laramie
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Cummins 5.9
Check for vacuum leaks. Clean your throttle body butterfly, especially the back side.

Is there an RPM where the miss consistently goes away? Say its idling at 750 RPM, if you slowly raise the RPM, is there a point where it stops missing, and is that repeatable? If so, what is that RPM?
 
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Kevin Anthony

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Hemi 5.7
Thank you for the tips. I would say literally right away after i press on the gas, probably just over 1000rpm. There really is no indication of any stutter or power loss once i apply the gas. But the CEL remains on and it's a constant stutter when coming to a stop
 

Oliver Closehauf

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2005 Laramie
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Cummins 5.9
Also try putting a vacuum gauge on a vacuum line and reading what vacuum is at idle. As soon as you open the throttle you will be getting more gas and less vacuum. I don't know what the spec is for your engine but I'm used to seeing well over 15 at idle.
 

DILLIGAF

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