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I don't "want" it to be the Head gasket

Discussion in '4th Gen 4Runners (2003-2009)' started by weydagizi, Apr 2, 2022.

  1. Apr 2, 2022 at 3:24 PM
    #1
    weydagizi

    weydagizi [OP] New Member

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    Hello everyone,

    I have a 2005 V6, 215k miles.
    I'm getting code P0306 misfire on cylinder 6 (always the same cylinder) occasionally. I start the engine, it shakes for a few seconds and then the CEL comes on with the VSC off and VSC Trac. I'm also losing coolant. First google search tells me head gasket, but I don't want to believe it (mostly cause that would be so expensive), so I tried to diagnose/fix the car as much as I could by myself:

    1. I've changed all the spark plugs and then I changed the ignition coil on cylinder 6 (original, Denso). Didn't help, I keep getting the code and the shaking occasionally.
    2. Measured engine compression: cylinders 1,3 and 5 were around 185-190psi; cylinders 2,4,6 were around 210-215psi.
    3. Borrowed a combustion leak detector, but the reference fluid did not change color, therefore it did not detect combustion gas in the radiator.
    4. Discovered that I'm losing coolant because of a leak on the passenger side bottom part of the radiator. I ordered a new radiator, I will change it in the coming days. The engine never overheats though, even when the coolant reservoir is empty and the radiator is missing coolant. The the temp gauge is always in the same place (the middle, where it should be) after the car gets to operating temp.

    Otherwise car drives well, accelerates well, MPGs are around 18-21, no white smoke comes out of it.
    I moved to the US from abroad, been driving this car for ~10k miles. Don't know any trustworthy mechanics, most of my colleagues use bikes (Cambridge, MA) so I can't ask them either.

    Before I run out of options, and go and find a mechanic and organize a leak down test, my questions are the following:
    1. I suppose the fact that the radiator is leaking pretty fast cannot really cause the misfire and the shaking, right?
    2. Can bad fuel injectors or bad O2 sensors cause the misfire and shaking? Shouldn't I get a code for these (or at least of the O2 sensor) if they are bad?

    Thank you!
     
  2. Apr 2, 2022 at 8:43 PM
    #2
    negusm

    negusm New Member

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    Yes, a sticky injector can cause the misfire.

    O2 sensor...not really a suspect.

    Swap injectors. See if the problem moves to a new cylinder.

    What does the plug for Cylinder 6 look like?

    I'm betting you have a bad injector that doesn't like to wake up.
     
  3. Apr 3, 2022 at 2:28 AM
    #3
    RLHOK

    RLHOK Keeper of the smoke and all things BBQ

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    If you are losing coolant, its a head gasket. Replace both sides, also water pump and thermostat and hoses while its apart.
     
  4. Apr 3, 2022 at 3:26 AM
    #4
    negusm

    negusm New Member

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    I don't think you read his post fully.

    No white smoke.
    No driveability issues after warm up.
    No detectable exhaust gasses in coolant.
    Leak found in radiator.

    Just because you lose coolant doesn't mean it has to be a head gasket. It could be but it's not looking likely.
     
  5. Apr 3, 2022 at 3:50 AM
    #5
    Kyblack76

    Kyblack76 New Member

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    Any bubbles in the radiator reservoir or radiator itself? Id think it would be over heating quite often. Swap injectors, like mentioned above,... 6 with the easiest one to pull/get to.
    Leaking intake manifold, by that cylinder 6? And it seals better, when warm. Just chuckin ideas around mate. Best of luck.
     
  6. Apr 3, 2022 at 9:48 AM
    #6
    RLHOK

    RLHOK Keeper of the smoke and all things BBQ

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    If he is losing coolant and there are no drips onto the ground, then I dont know what else it could be. Not saying I am 100% correct by my bet is on a head gasket. Pressure test the radiator to find a leak.
     
  7. Apr 3, 2022 at 5:40 PM
    #7
    negusm

    negusm New Member

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    Why should he pressure test the radiator? He's leaking out of his radiator. He said so himself. He found the leak too.
     
  8. Apr 3, 2022 at 5:41 PM
    #8
    RLHOK

    RLHOK Keeper of the smoke and all things BBQ

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    I missed the post where he said he found the leak.
     
  9. Apr 3, 2022 at 5:42 PM
    #9
    negusm

    negusm New Member

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    It's in THE FIRST POST!
     
    4scooter19 likes this.
  10. Apr 3, 2022 at 8:18 PM
    #10
    4scooter19

    4scooter19 New Member

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    :rofl:
    Reading is difficult
     
  11. Apr 4, 2022 at 6:41 PM
    #11
    weydagizi

    weydagizi [OP] New Member

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    Thank you all for the advice and for trying to help. The new radiator just arrived today, I'll swap the old one out in the coming week or so.

    I also bought remanufactured Denso injectors, set of 6 for 50 bucks on Ebay. I thought if I go through the trouble of pulling it apart, I might as well change all the injectors.

    I'll check back in a few weeks and let y'all know how it went.

    Cheers!
     
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  12. Apr 4, 2022 at 6:43 PM
    #12
    negusm

    negusm New Member

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    $50?

    I doubt those are legit.
     
  13. Apr 4, 2022 at 7:27 PM
    #13
    weydagizi

    weydagizi [OP] New Member

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    Let's see... there are plenty of remanufactured options on Ebay for 50-80 bucks per set of 6. This seller I chose is from California and had good reviews. I'll let you know how the injectors worked out.
     
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  14. Apr 4, 2022 at 8:14 PM
    #14
    negusm

    negusm New Member

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    Please report back, whatever happens.
     
  15. Apr 21, 2022 at 8:21 PM
    #15
    weydagizi

    weydagizi [OP] New Member

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    Okay so last weekend I managed to finish all the work on the car.
    I changed the radiator without issues and replaced the injectors with the 50 dollar ebay renewed Denso injectors as well. The work wasn't too bad thanks to the youtube videos, but I worked a total of 6 hours from start to finish, mostly cause of some things being stuck or hard to reach. I also cleaned the throttle body along the way, with throttle body cleaning spray (it didn't look too bad though). Since last Saturday, I haven't got the occasional rough idling with the cylinder 6 misfire code, but it's still too early to celebrate.

    Also because now I keep getting a P0172 and P0175 (bank1 and bank 2 has too much fuel or not enough air) codes and I never had these codes before...
    I cleared them, went back and changed the o-ring on the throttle body (first time I just reused the old one) and cleaned the MAF sensor with MAF cleaning spray. Checked all vacuum connections to make sure everything was back in place, but I keep getting the codes back every 5-10 miles or so after I clear them.

    Could it be cause of the ebay injectors? Strangely the car seems to run smoother than before, might even accelerate better (or I might just be imagining it), rpms at idle are stable around 670-690 (according to the code reader), MPGs are around 17-18 (I don't usually do highways), no smoke from the exhaust.

    Please share your thoughts, I don't really know what the next step should be. I think I could still negotiate a refund on the injectors, if you think those are the culprit. Thanks!
     
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  16. Apr 21, 2022 at 8:31 PM
    #16
    negusm

    negusm New Member

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    Yeah. My vote is bad injectors. No one is going to remanufacture injectors for $8 an injector.

    They are probably leaking at idle...causing a rich condition... but working ok during acceleration.

    I'd get a full set from a reputable reman shop that's flow tested an oem set. Should be $300.
     
    PhantomTweak likes this.

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