2012 used Prius rough idle and driving at slower speeds

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Anita24, Jun 12, 2022.

  1. Anita24

    Anita24 New Member

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    We bought a 2012 Prius used with 203,000 miles on it. Has the brake booster replaced about 2-3 months ago at Toyota ($3000). Car had a miss. Spark plugs and coils replaced. Drove on a 9 hour trip miss got worse and on the way home it started rough idle and rough acceleration. It looks like someone had the head casket replaced before we purchased. He has replaced the EGR valve, cleaned the intake manifold and MAF AMD MAP sensors. The car will some have the triangle, vcs, and car with exclamation light up. Also the hybrid system failure light. Car has shut down a few times but when code is cleared starts back up. Took it to Toyota said need new intake manifold and EGR pipe? Wanting another $2300. We know have $9000 after the booster had to keep throwing money at it. Any suggestions?
     
  2. CR94

    CR94 Senior Member

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    But they never cleaned out the old manifold or the EGR cooler (which is sometimes called "pipe," and not to be confused with the much simpler, smaller pipe that connects the EGR valve to the manifold)? Cleaning the manifold is a relatively easy do-it-yourself project.

    What's the code? You need to find out what it's telling you before clearing it.

    You can find numerous related threads on Priuschat from people with similar issues.
     
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  3. Anita24

    Anita24 New Member

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    P0301. Intake all above mentioned cleaned.
     
  4. bisco

    bisco cookie crumbler

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  5. Anita24

    Anita24 New Member

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    We have replaced the spark plugs with denso in case the one we ordered from Amazon are bad. Car is still rough idling and when dad is pushed it doesn’t rev the engine also when pushing the petal to the floor when driving it it doesn’t want to accelerate this can be intermittent. We have cleaned all parts swapped some of the sensors with my 2012 prius like MAF, MAP, CAM, throttle body. No improvement.
     
  6. rjparker

    rjparker Tu Humilde Sirviente

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    Sometimes it seems head gasket issues on these engines deserve a casket.

    1. How do you know a head gasket job was done?
    2. Who was the car seller? A Toyota dealer or a private party?
    3. Has it lost any coolant from the passenger side reservoir?

    $2300 must be a new intake, egr valve and egr cooler. A stuck open egr valve might cause some of your issues. But that kind of error is opposite of the normal Prius egr problem, eg the egr system clogs up.

    The head gasket might still be the problem. If the seller told you it was replaced, there is 98% certainty the engine had a head gasket problem. They are common on this engine. If it was "fixed" it may have been a poor diy job or sealant was added to the coolant, a temporary fix.

    Concerning the egr, check out The Car Care Nut youtube channel. He has an egr video showing how to check for a sticking egr valve by temporarily blocking the egr tube. It is quick and easy and could verify the dealer diagnosis. Don't expect a dealer to do the check.

    So it may be time to find an independent hybrid mechanic in your area. Often an independent will save you 1/3 to 1/2 over a dealer. Sometimes the right guy with hybrid experience can more accurately diagnose than your average dealer mechanic.

    Finally, at a dealer you generally talk to a service advisor, not the mechanic. Often the service advisor is on commission and is typically not a trained mechanic. It is very possible to get upsold by a service advisor with minimal technical background. Find an independent with Toyota hybrid experience.
     
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  7. Anita24

    Anita24 New Member

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    Private seller. We have watched that video and it’s not the egr. I read something else about to much vacuum could cause it it not to accelerate but it didn’t say how to test for the problem. My husband noticed it didn’t have the original factory head casket on it. He read it was a better one. No coolant or oil pass. We had the head casket replaced on mine a couple months back and now this with his trying to avoid another $2000 to 3,000.
     
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  8. Anita24

    Anita24 New Member

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    Also I was wrong about the code it P0101.
     
  9. rjparker

    rjparker Tu Humilde Sirviente

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    Its Gasket not Casket. The quality of the gasket is not the issue; often the job is done incorrectly. Sometimes there are warped or bent assemblies. A private seller is suspect.

    So did your husband do the egr blocking check?

    That code is MAF which is often still defective when not replaced with oem Toyota. Sometimes the original oem is better than the new aftermarket part. Still think you need an independent mechanic.
     
  10. Anita24

    Anita24 New Member

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    Pardon my misspelling! He replaced the MAF sensor with factory part that was in my 2012 and working. It’s not doing what my car did when the head GASKET blew. If anyone has dealt with a vacuum problem that caused you not to be able to go when pressing the gas that would possibly be helpful. We have recently paid $2800 for my head, $3000 for his brake booster and my daughters 2008 with 295,000 miles hybrid battery just failed. So while I would love to have money to keep throwing around we are trying to fix it if possible at home. Thanks
     
  11. Mendel Leisk

    Mendel Leisk Underfoot

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    P0301 indicates cylinder one “misfire”, which is very common with 3rd gen Prius head gasket failure; the failures are almost always at cylinder one, or two.

    Leak down test and boroscope inspection is the usual course to determine head gasket integrity.

    I would determine what’s going on with the head gasket first, resolve as needed, and immediately thereafter clean the complete EGR system, including the intake manifold.

    more info in my signature. If you’re on a phone, turn it landscape to see signature.


    Ok, see the code was P0101. There's probably some worthwhile in the above, but I'll strike it out. Ugh...: between the "possible" head gasket issues, hybrid battery warnings, I think you've got yourself a Toyota lemon. Or two? The amount you're spending on those rivals me and the missus' dental expenses this year.
     
    #11 Mendel Leisk, Jun 16, 2022
    Last edited: Jun 16, 2022
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  12. Anita24

    Anita24 New Member

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    Have you ever heard of problem when pushing the case the car won’t rev most of the time. I read something about to much vacuum in the intake manifold. We have not try the fuel injectors or pump.
     
  13. Anita24

    Anita24 New Member

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    Just wanted to update in case anyone has this happen. We have replaced sensors, cleaned all the parts, replaced spark plugs and coils. My husband decided to try to do the leak down test and went to turn the engine and the harmonic balancer was so loose it was barely on. He tightened it up and no more problems at this point.
     
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  14. burebista

    burebista Member

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    Thanks for coming back with your solution. (y)
    For me it's the first time when I read about harmonic balancer and rough idle and driving at lower speeds.
    Good to know. :)
     
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