Rough idle? P0171, P0174? Here's what you need to check first!!!

Discussion in 'How To Section' started by Lane24, Dec 10, 2009.

Car Parts
  1. Berg

    Berg Full Access Members

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    did the part you bought have new elbows on both sides of it? the elbow on the end that connects by the throttle body on mine was melted closed.now its runs like a dream and even sounds different too
     
  2. glen615

    glen615 New Member

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    Yes the hose came with both elbows and the pcv.

    Yesterday I replaced the MAS with a new one and that did nothing and I also replaced the fuel filter but no luck either. Tomorrow I will swap both upstream 02 sensors and possibly the fuel pressure regulator and after that I have no idea what else can be generatoring both P0171 & P0174 codes.

    Also, yesterday I fed smoke through the brake booster line from a fog machine hoping to see it leak somewhere but it seemed airtight everywhere even checked under the car. I put s good amount of smoke in too

    Taking a break today for the holiday but back at it again tomorrow. Have a happy thanksgiving!
     
  3. Berg

    Berg Full Access Members

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    sux !
     
  4. glen615

    glen615 New Member

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    Well it turns out it was the fuel pump. Just goes to show that the lean codes
    generally associated with a vacuum leak can sometimes be a more involved. Fortunately I found a guy to drop the tank and replace it with all for under $450.

    I returned the o2 sensors & fuel pressure regulator. I hope my experience helps someone.
    Thanks for the input!!!
     
  5. Lane24

    Lane24 technical advisor

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    Glad you found your problem !!! Like the title says , these vacuum leaks and simple things are what you need to check first before you let someone talk you into spending the $$$$$$... and a good percentage of the time that's all the problem is....but unfortunatley, sometimes the problem goes a little deeper. Thanks for sharing your experience in this thread. It's going to help someone for sure.
     
  6. ohillny

    ohillny Member

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    Life and financial savers

    I have exact same symptoms down to the whistling and being that it is -3 and -22 wind chill here in rochester the EX would not get me were I needed to be this morning thanks for this post I am sure this is my problem as I have the same codes and check engine light on since replacing my coils and plugs probably damaged that hose then.. Once again thanks for this post!!

     
  7. ohillny

    ohillny Member

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    she is stalling again

    I replaced pcv and hose to the back of the intake was running a lil better clean MAF sensor still the same idle. Temp dropped last night this morning she was running real rough. I also was going to change the fuel vapor separator tube this is the one that goes to the brake booster. I don't think this is the problem but it kind of worn out also. Still I am at a lost any other suggestions? should I give the TB and that whole area a good cleaning? Suggestions are greatly welcomed..
     
  8. bedrck46

    bedrck46 Guest

    You may want to clean the exhaust ports in the TB which involves removing the TB

    also would suggest new plugs,cop's, etc
     
  9. ohillny

    ohillny Member

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    THanks

    Yeah gonna have to get in depth with it, seemed like I started having these problems after replacing all my plugs and coils honestly.. THanks again for the suggestions..
     
  10. bryanaceron

    bryanaceron New Member

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    had the same problems did the same replacing all the parts and come to find out the new set of spark plugs were defected. now runs like a champ
     

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