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Engine Knocking on deceleration (btwn 800-2000 rpm)

Discussion in '2nd Gen. Tacomas (2005-2015)' started by Renquest, Dec 31, 2018.

  1. Dec 31, 2018 at 5:01 PM
    #1
    Renquest

    Renquest [OP] Member

    Joined:
    Jul 20, 2014
    Member:
    #134289
    Messages:
    5
    Gender:
    Male
    Austin, Tx
    Vehicle:
    05 TRD Taco 4x4
    Good Morning/Afternoon/Evening to you all.

    I'm dealing with an engine knocking on deceleration.

    Taco Spec:
    - 2005 Crew Cab V6 4.0L TRD Sport Manual 6SPD
    - 117k miles.
    - Only maintenance done has been oil changes. (I accept blame for this)

    Symptoms:
    - Knocking has been occurring for about a month now.
    - Knocking occurs only when engine is warm. (no engine knocking on cold start)
    - After engine is warm, knocking is somewhat audible at idle.
    - After engine is warm, knocking is very audible when decelerating (take foot off the gas) between 2000 down to 800 RPM.

    Actions Taken:
    - Been using 91 octane for a little over a year.
    - Replaced spark plugs with iridium plugs (NGK LFR6C-11) properly gapped.
    - Cleaned MAF sensor.
    - Added a can of seafoam to gas tank.
    - Added seafoam to crankcase and ran for approx 100 miles.
    - Then changed oil (Mobile1 Synthetic) and added Lucas oil heavy duty oil stabilizer.
    - Belts look good no cracking, stripping.

    Symptoms remain the same.

    About to take the taco in for proper diagnoses, but wanted to see if anyone has any additional input that I may have overlooked.
     
  2. Dec 31, 2018 at 10:59 PM
    #2
    Longtech

    Longtech i fcked up and bought a 2wd

    Joined:
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    Long
    Santa Ana, CA
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    From the symptoms. Sounds like it may be a rod knock. Get under the engine and have some rev up and let off. You can prob hear it better from below if it is a rod knock.
     
    Renquest [OP] likes this.
  3. Dec 31, 2018 at 11:08 PM
    #3
    Steves104x4

    Steves104x4 Well-Known Member

    Joined:
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    Steve
    Buffalo NY
    Vehicle:
    2010 RC 2.7 4x4
    BUCKLE UP! It makes it harder for Aliens to pull you out of your Truck.
    When is the last time you lubed the driveshaft u joints? Check the center bearing, too
     
    Renquest [OP] likes this.
  4. Jan 1, 2019 at 6:01 AM
    #4
    Renquest

    Renquest [OP] Member

    Joined:
    Jul 20, 2014
    Member:
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    Messages:
    5
    Gender:
    Male
    Austin, Tx
    Vehicle:
    05 TRD Taco 4x4
    Thanks for your response. Got under the engine after the truck was warm and rev'd the engine. It seems like a rod knock for sure. What is a ballpark on the amount that would cost to replace? $1K or higher?
     
  5. Jan 1, 2019 at 6:08 AM
    #5
    Renquest

    Renquest [OP] Member

    Joined:
    Jul 20, 2014
    Member:
    #134289
    Messages:
    5
    Gender:
    Male
    Austin, Tx
    Vehicle:
    05 TRD Taco 4x4
    Thanks for responding. I will be honest. I have never lubed the driveshaft u joints. So guess what I will be doing today :)
     
  6. Jan 1, 2019 at 6:09 AM
    #6
    Fullboogie

    Fullboogie Well-Known Member

    Joined:
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    Dave
    Houston
    Vehicle:
    2007 Prerunner & 2008 4Runner
    Don't jump to the worst conclusion yet. Get it looked at by a pro. "Rod knock" is extremely unusual, more so for a 117K mile engine.
     
    Renquest [OP] likes this.
  7. Jan 9, 2019 at 2:45 PM
    #7
    Renquest

    Renquest [OP] Member

    Joined:
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    Member:
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    Messages:
    5
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    Male
    Austin, Tx
    Vehicle:
    05 TRD Taco 4x4
    Just wanted to update the forum.

    Took the taco to a mechanic and it is the driver's side catalytic converter that is rattling. The mechanic stated that it is not affecting the engine as there is no 'check engine' light at the moment. Since there are no codes being thrown, the mechanic could not guarantee that replacing driver's side cat would resolve the issue. The reason given is that is might be a different cat. The part alone was $800-$850 and i would have to leave it over night.

    How many labor hours to replace a driver side cat? I would assume about 3hrs, if the part is available.
     
  8. Jan 9, 2019 at 2:48 PM
    #8
    andrew61987

    andrew61987 Well-Known Member

    Joined:
    Jun 2, 2015
    Member:
    #156610
    Messages:
    1,149
    Vehicle:
    2008 Access Cab 4WD, 2.7L 5 speed
    What exactly is rattling? The material inside the cat or is it just loose somehow? Maybe it's just a heat shield or something and you can get under there and replace a bolt/tie it off with the bail wire and call it good. Go tap around with a mallet and see what's actually rattling.
     
    Renquest [OP] likes this.
  9. Jan 9, 2019 at 2:51 PM
    #9
    Renquest

    Renquest [OP] Member

    Joined:
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    Member:
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    Austin, Tx
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    05 TRD Taco 4x4
    It is something inside the cat that is rattling. I checked the heat shield before I took it in. Heat shield wasn't loose at all.
     
  10. Jan 9, 2019 at 6:13 PM
    #10
    Longtech

    Longtech i fcked up and bought a 2wd

    Joined:
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    Male
    First Name:
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    Santa Ana, CA
    Vehicle:
    15' OR 2WD
    Thats way better than a rod knock then! Theres a honeycomb looking partition inside the cat. Rare but they do come apart inside as it degrades over time. Ive seen some where it causes poor engine performance and driveabilitly due to the pieces inside clogging the flow of exhaust. My shop charges 4hrs labor to replace one cat. So 3hrs aint bad.
     
    Renquest [OP] likes this.

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