2009 Hemi Rough Idle

Discussion in 'Dodge Charger Mechanical Problems and Questions' started by disdoc, Mar 6, 2017.

  1. disdoc

    disdoc New Member

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    Location:
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    Vehicle:
    Charger Police
    Vehicle Year:
    6th Gen - 2009
    Trim?:
    Police
    Color?:
    Dark Titanium
    Hello to all. I am hoping the knowledgeable people here can lend me their expertise. I am aware that similar problems have been posted in other threads but I have not been able to find anything similar to my issue at hand. I will try and give as much info as I can.

    I have a 2009 Dodge Charger Police with the Hemi. It is completely stock and never seen police duty service. Have had it since new. It has had all its maintenance as required. Current mileage is 174,000 kms (108,118 miles). PCM is flashed with the most recent version. O2 sensors were replaced about 20,000 kms ago.

    A few days ago the vehicle has developed a rough idle. It is intermittent, and there is no common denominator as to when it will occur. Some trips it doesn't happen at all and idles fine. Other times I will come to a stop and the rough idle is there. Happens while either in gear or not. Very similar to a cylinder that is misfiring in feel (if that makes sense). Sometimes the rough idle will continue and other times after the car is parked and then restarted, it goes away. I should mention that it appears to only occur after the car is at operating temperature. It does not seem to affect acceleration/performance/mileage and there is no missing or hesitation while accelerating or under load.

    There are no trouble codes stored nor has any CEL come on. In an attempt to rectify the condition I replaced the spark plugs (have always used stock plugs) and checked all the coil connections. The old spark plugs had no abnormal wear or the likes on them. I also cleaned the throttle body and have run through two tanks of gas with injector cleaner. To eliminate fuel contamination, I also filled up at two different gas station companies. The PVC valve was replaced and the IAT sensor was checked. Have also checked all vacuum lines for any defects as well as any abnormalities in wiring (obvious breaks, loose grounds, etc).

    I have read other posts where they mentioned the EGR valve, however my version does not have one (yes I looked, know what it looks like and where it is on other models). I have scheduled an appointment at the dealership however, I am extremely hesitant to take it to them. The reason is that unless the vehicle has a trouble code or presents with the problem while in their hands, the odds are I will spend money for them to do nothing and tell me to return when the problem is happening or if a trouble code comes up. I can't predict when the rough idle will happen so can't take it to them when it does.

    I realize it could be a lot of things causing the issue but can anyone think of something else it may be? I like to eliminate the simple things first and work my way up. I have hear quite a few people tracing it to carbon build up on the exhaust valves but I am hoping it is not that. Because it is inconsistent in happening, I'm thinking it may not be that.
     
    Last edited: Mar 6, 2017
  2. 3 G BEE

    3 G BEE New Member

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    Vehicle Year:
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    Trim?:
    SuperBee
    Color?:
    Detonator Yellow
    How did the plugs look when they were changed ? I would say possible Plug issue or Coil issue, Moisture or not fully seated. You may also want to check torque on you intake bolts, they are prone to loosen causing vac loss.
     
  3. TheHandler

    TheHandler Member

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    6th Gen - 2010
    Trim?:
    R/T
    Color?:
    Brilliant Black
    How did you check for codes? How many days has this been happening?
     
  4. jrhemi

    jrhemi Member

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    Midnight Blue
    may have a wiped out cam lobe. Vacuum leak?
     
  5. deanpasquale

    deanpasquale New Member

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    Try throttle body service. You might have built up carbon that is keeping the throttle plate open. Spray cleaner on it and brush with a toothbrush. A body shop manager at a Chrysler dealer found it on my 2006.
     
  6. djalbin

    djalbin Active Member

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    Check the torque on the intake manifold bolts ... they may have backed out and not tightened down to 9 ft. lbs. (12 N·m for our metric members).
    Tighten in sequence from the middle bolts towards the outside in a crisscross pattern.
    .
     
  7. TheHandler

    TheHandler Member

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    Do the RPM's drop when things get rough? I know with my '10 that occurrs at times when I pull up to a light. The problem for me is most likely software related. Some have said a PCM flash would correct.
     

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