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Lexus RX 400h Engine Problems

mkkidmkkid Posts: 11
Since day one (now got 8000 miles) I often get a stuttering or engine miss feeling at steady 30-40 mph. This problem isn't constant, but it does bother me. Anyone else experience this?


  • Hello,
    I just got my 400h last weekend. When I test drove it, the engine was as still and quiet as could be at startup when still in the "park" position. Now that I have it in my garage, I am noticing different behavior. When I turn the key position, it is completely still at first for about 3 seconds. After that, I will still be in the 'park" position, but it will feel like the engine has come to life and I actually feel it running, like I would feel the engine of a non hybrid car. Is this normal?
  • katzjamrkatzjamr Posts: 146
    This is completely normal. The 400h will start up during a cold start to circulate oil, to get the catalytic converter up to temp, to provide heat on cold days or to charge the battery when it is low. This can happen at any time, but it will always fire up when on a cold start. It feels like the engine in a non hybrid car because that is exactly what is running. It is alittle louder on first start up then quieter when warm. Enjoy your 4ooh.
  • lexus400lexus400 Posts: 8
    I had this problem with less than 1000 miles and returned to dealer. They test drove the car and said that if many others were having this problem they would work on solution via software reconfiguration. At 5000 miles, the service manager, district manager, dealer tech have all driven and MAYBE admit that there is a problem. They finally called engineers and said that there is a patch coming out-strange that I am the only one who MAYBE feels it but they are working as we speak on a patch. My issue is a stuttering/pulsing at 37-42 mph and I find it quite annoying. They have asked me to wait and see if the issue is resolved via software fix. Don't know what choice I have now after spending 52,000K on this car and hoping that it would have great gas mileage-which is not close to quote-and feeling good about the hybrid aspects for the economy on my pocket and the environmental impact that I would be contributing to with this purchase. I would love to know if others are having this issue. They are saying that some people are more sensitive than others so I would love to hear from you if you are having the same issue.
  • mkkidmkkid Posts: 11
    There's some degree of comfort knowing "others" experience this problem. I've simply "put up with it" but with your info, will push my dealer into action (if that's possible.)
    Mine is a problem that occurs in same speed range as yours and probably happens 30-40 percent of time time. None of the gauges (mpg, etc) show any corresponding "fluttering" when the engine pulsing happens.
  • mkkidmkkid Posts: 11
    Following up on my previous response to you, I first called Lexus tech support people to see if any service bulletins, etc. had come out on this stuttering problem. They could find NOTHING. Then I called my Lexus dealer service expert and he had no idea what I was describing much less a solution offering only to do a "road test."
    If you ever find a solution, pls respond.
  • lexus400lexus400 Posts: 8
    As of now they are calling it a nibble and say that they are in the process of a computer patch that will fix the issue. After driving my car 500 miles, I was sure that it was a tire issue. They assured me that it was not. The service man said that he felt the pulsing. Later I had to return for the service manager to test drive-he couldn't feel it he said. Later I had to return to have the district manager drive it. He said that he couldn't feel it, and said that I was the only one with the issue. Yet I then heard that they had a lady with the same issue in several hours earlier-different speed-and then he said that they were working on a computer patch to address this issue. Why would they be working on it and have it due end of April if I am the only one with the issue? I am hopeful that it will resolve the issue-I know can tell you exactly when I hit 37-42 without looking at the speedometer and now realize how often I drive in that range.
  • You would be interested to know that when I picked up my Rx I almost turned around and gave it back because the "nibbling" was so profound. At times I don't feel it. Let me know if there's a fix.
  • wth18359wth18359 Posts: 2
    I'm glad (well, not really) to hear that someone else is experiencing a similar problem. I'm feeling what I would call a vibration at 42-45 MPH. I first thought it was tires, but after having them balanced, then installing winter tires, I'm convinced it is something else. It comes and goes. I almost always feel it when the engine is cold, and usually under light acceleration. There is no indication of anything odd on the display, such as quick switching from battery to ICE. The dealer has tried to find the problem twice, and they can't really feel it, let alone find it. I'm giving the dealer one more change to figure it out, then I'm calling Lexus.
  • lexus400lexus400 Posts: 8
    Are you still experiencing this issue. I have really been run around at my local dealer and Lexus customer care. At first this is a new problem, then I am the only person having this problem-then there is a fix in the works-interesting if I am the only one with the issue-or is a fix in the works. Since 500 miles I have been reporting the issue, I now have 10,000 miles and feel like I am being shaken to pieces between 37-42 mph. I am now onto the National Center of Dispute-and can't get the guy to even return my calls. For +$55,000 by the time that I added on all of the extras-I feel that I have a lemon or a car that wasn't ready for release. I have waitied now 4 months for the next month there will be a fix, now mid June according to the dealer, mid August according to Lexus. Anyone else with these issues-any fixes that have worked-any other proposed fixes????

  • gagricegagrice San DiegoPosts: 28,678
    I am being shaken to pieces between 37-42 mph

    That sounds bad. Most of our surface streets are 35-40 MPH. Does your state have a Lemon Law. If you have all the dates you were at the dealer I would try to invoke the law. They may be trying to jack you around till the warranty expires. I would get a signed statement each time you take it in, stating they are working on the problem. Keep us posted.
  • lexus400lexus400 Posts: 8
    Thanks, I even told them that I was going to come into the service center every week. The manager asked why I would do that-I said that there was some law called a lemon law where I had to be in for something like 3 visits with them unable to fix the car. He flat out told me that I could tell them that and that they would just say that they couldn't duplicate the problem. I really fell like they are playing cat and mouse with me. My husband was ready to buy a new Lexus, and that has certainly been put on hold or maybe even out of the question. Thanks for the advice. I am trying to move on with the National Center for disputes but the guy that is supposed to return a call within 24 hours won't respond either. Guess next time I should buy a hunk of junk then I will expect a hunk of junk.

    Thanks for your response and I will keep you all posted.
  • doneby2010doneby2010 Posts: 27
    Have had 400h for 6 months (and 5000 miles) and don't have this problem. The car has a smooth ride and has no vibrations similar to what you described.

  • bobgailbobgail Posts: 12
    I am really concerned about all the reports of the engine "stuttering" at about 35-40 mph. Has anyone gotten a reasonable answer from a dealer? I have the 400H since last December. (05) I have driven it over 9000 miles and it has really been the "perfect". Of course, I am worried that the problem that has been reported may be inherent in the car. If so, I want to "head it off at the pass".

    Regarding the free service at 5k miles. I was unhappy with the dealer service for the following reasons;

    -they had me wait at least 2 hours before they reported that the service was completed.
    -they did not rotate the tires. (I marked them so I could tell)
    -they ignored the issues I brought to their attention. eg. squeeks.

    The dealer has all kinds of services they subscribe to in order to get a report about how "wonderful" they were with my car. When they called me, I let them have it! The next day, the customer service rep from the dealer called me up to find out why I was so unhappy with their service. She asked me what they could do to rectify the problems. I said; Pick up my car and leave me the loaner until you deliver it to me with the service completed and do it next time for no charge. They agreed and sent me a letter confirming the free service. We will see about the car pick up.

    Another thought-- The prices they charge for an oil change and tire rotation are outrageous. I think its about $70 in Florida. Not as bad as getting a Porche done for $300. I have always done my own oil changes on the Lexus rx300- vin tage 2000. I use only Mobile 1 and Toyota oil filters. The car has 189k miles and runs like the day I bought it. I would like to sell the car, but when people see the milage, they run as fast as they can.

    Good luck with the stuttering.

  • lexus400lexus400 Posts: 8
    Consider yourself one of the lucky ones. My dealer told me 2 weeks ago that he has 6 of them with this issue and that mine is the worst one that he has. Hope that they will address this issue and resolve it soon. I love the hybrid idea but need to be able to drive between 37-42 without nibbles/vibrations.
  • lxpatellxpatel Posts: 34
    I haven't had any problems with it either, 8k miles and 8 mos in service. Great gas mileage on highway, got 27 on trip from LA to San Diego and back, 80+ all the way.
  • jordanfjordanf Posts: 15
    Could someone tell me the difference between an interference and non-interference engine
  • lexus400lexus400 Posts: 8
    Well, the car still nibbles with 10,000 miles. They said the computer fix would be here July 4th week, it is the 17th and now they are saying it takes 30 days to get it from Japan-but I will be one of the first to get it.

    My father drove the car after taking up to the airport, and he said that he thought that he was going to get sick from the rocking/pulsing that was going on around 40 mph.

    I have called an arbitrator to start process and if they don't have a soulution very soon, I guess that is the next step. I should have given them the car back the first time because it was within the 30 day, but I believed them when they told me they were working on a fix. I thought that it would not be the right thing to do to give them the car back and demand my money back although at that point I had the legal right to do that. I thought that I was standing by my word to buy the car and that they would stand by their word to deliver a car worthy of the $55,000 price tag and Lexus name. Guess they are trying to prove me wrong and a fool!
  • PFFlyer@EdmundsPFFlyer@Edmunds Pennsylvania Furnace, PAPosts: 5,808
    In an interference engine, the valves open far enough into the cylinders that they "interfere" with the piston's space. The interference design actually improves the efficiency of the engine due to the wider opening valves, but if you run into a problem and the timing is off, the valves can actually strike the pistons, which is NOT a good thing at all.


    Moderator - Hatchbacks & Hybrid Vehicles

  • dcaenendcaenen Posts: 1
    Had my Hybrid computer replaced with the new one yesterday, and the Nibbles are completely gone. If this bothers you too, I highly recommend you check it out. I guess there is no Service Bulletin.... my dealer didn't know about it, but the Toyota "Field Mechanical Specialist" did... Took 2 Days to get the new computer though... It was worth it.

  • swift725swift725 Posts: 2
    I love this truck but now when i start it in the morning even if its warm outside or cold, it runs real rough the first 5 minuets or so and hesitates. Replaced coil, plugs, rotor, throttle positioning valve, idle air sensor, and had injectors sent out and cleaned with new seals and screens. ALSO when truck is parked after runing to work or the store, i get back in it in about an hour and its hard starting. But if it sits all night it will start great just run rough for a bit. Or if I start it after its been hot or ran it before 45 minuets to an hour it will not be hard starting.... Please Help?? THX :confuse:
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