I have a 2007 GS450h and I've noticed that once the engine has warmed up if I stop in traffic and the engine doesn't cut out that the idle is quite lumpy passing vibration through the steering wheel and gear stick. I've also noticed that when it runs like this there's something knocking underneath the car. I'm concerned this could be something to do with the Hybrid inverter/converter.

Has anyone else experienced this lumpy idling?

[quote name='GS Sport' timestamp='1306261834' post='754988']
I have a 2007 GS450h and I've noticed that once the engine has warmed up if I stop in traffic and the engine doesn't cut out that the idle is quite lumpy passing vibration through the steering wheel and gear stick. I've also noticed that when it runs like this there's something knocking underneath the car. I'm concerned this could be something to do with the Hybrid inverter/converter.

Has anyone else experienced this lumpy idling?
[/quote]
Hi, yes mine has what I describe as a raw idle, quite noisy with quite a violent shake when it starts/stops when warm but have never heard a knock from underneath.

Might pay to have it checked out.

[quote name='tonyricha' timestamp='1306338731' post='755033']
[quote name='GS Sport' timestamp='1306261834' post='754988']
I have a 2007 GS450h and I've noticed that once the engine has warmed up if I stop in traffic and the engine doesn't cut out that the idle is quite lumpy passing vibration through the steering wheel and gear stick. I've also noticed that when it runs like this there's something knocking underneath the car. I'm concerned this could be something to do with the Hybrid inverter/converter.

Has anyone else experienced this lumpy idling?
[/quote]
Hi, yes mine has what I describe as a raw idle, quite noisy with quite a violent shake when it starts/stops when warm but have never heard a knock from underneath.

Might pay to have it checked out.
[/quote]
Yeah it's going tomorrow. Going to Toyota though, not Lexus as they were very unaccommodating for someone who works full time. My theory is they're the same company and both build hybrids so I'll see what they say first.

I'll update if they find anything.

Mine does the same, the engine feels as if it's on the edge of a stall running very lumpy, and then finally cuts out sending a judder through the car.
It happens at time when I would expect the engine to be stopped.

There is no knocking from under the car though, sounds like you have something loose.

I did ask at the Lexus dealer about the lumpy idling, they asked me to demonstrate to them, but of course the car was working perfectly when I tried.

The car has been doing this maybe one stop in every four the car makes.

This has been happening for the two year that I've had the car, and has not gotten any worse.

Please keep us posted of any investigation you have done.

OK, put the car into Toyota today just for an initial look. The Technician came out and luckily I could replicate the judder and knocking. He said that they had had a few faulty coils with the Toyota Hybrid range and this produced a similar symptoms. He said the knocking could actually be unburned fuel igniting in the the exhaust causing vibration through the car. The car's going in next Wednesday so they can test all the coils (one per cylinder these days). I'll post the results.

I have heard that the Valve Spring recall problem could also produce lumpy idling because of the weak springs not fully closing the valve but mine had this work done last year when they started the recall so shouldn't be that.

See what happens Wednesday.

There was no difference in the problem for me before or after the valve spring recall.

As for unburned fuel in the exhaust. I can see that causing vibration, but would it also cause the engine to keep running when you expect it to stop.
To me it seems like some fuel is getting into some of the cylinders when it shouldnt.
To me the the vibration always feels like a car that is running on after the ignition is turned off.


I'm only guessing, I'm not a technician.
If they fix it by changing the coils, they will obviously be correct. It will be interesting to find out.

Would that fault be covered under the first three years warranty?
When I first reported the problem the are was under three years old, and now it's older than three. Maybe it can still be done for free.

Did you get any indication of likely costs?
If yours is done under warranty, would you ask the cost would be without a warranty.

Thanks.

Right, Toyota have recommended changing all 6 coils! When I questioned further they said they had only actually tested 4 but as 4 were failing recommended replacing all 6. I asked if this would definitely fix the problem as they quoted nearly £900.00!!! They said they were pretty confident but couldn't guarantee it. My feeling is that if all 6 coils were failing there would be some kind of warning light because the emissions would be all over the place and secondly I'd be noticing a dramatic lack in performance (which I'm not).

So at the moment I don't have a clue. They could be right as they say it's happened a few times with the Toyota Hybrids but £900.00 is a hell of a gamble. Think for now I'll just put up with it until either it gets worse or some system error comes up.

Hi, I don’t know how many miles your car has done but I am really getting fed up with this sort of expenditure on a car costing close to 50k, if its done less than 60k then I would defiantly contact customer services, ok your car is over 3 years old and out of warranty, but so what.
Why should it be 60k miles or 3 years, they must be fairly confident that there cars should go 60k miles without too many problems, but as soon as they pass 3 years old then that’s it, if parts are guaranteed for 60k miles then it shouldn’t matter how long that takes. It will take me 13 years to cover 60k miles.
So if I brought a brand new car, left it in my garage for 3 years, then drove it for the first time and got a problem, it wouldn’t be covered because it would be out of warranty, what I would like to no is how many parts on a car would fail due to time and not usage?
So come on Lexus your soon let us no how well you are doing in customer satisfaction polls with reliability, so let have a 5 year warranty, if kia can do it I am sure you can.

[quote name='GS Sport' timestamp='1307123176' post='755667']
Right, Toyota have recommended changing all 6 coils! When I questioned further they said they had only actually tested 4 but as 4 were failing recommended replacing all 6. I asked if this would definitely fix the problem as they quoted nearly £900.00!!! They said they were pretty confident but couldn't guarantee it. My feeling is that if all 6 coils were failing there would be some kind of warning light because the emissions would be all over the place and secondly I'd be noticing a dramatic lack in performance (which I'm not).

So at the moment I don't have a clue. They could be right as they say it's happened a few times with the Toyota Hybrids but £900.00 is a hell of a gamble. Think for now I'll just put up with it until either it gets worse or some system error comes up.
[/quote]

Well like I said before, it's not gotten any worse on mine in two years I've had the car, the car is 4 years old now with just over 60k.
However if there is some think loose on the car causing the knocking, it's fair to assume that the knock will get worse over time.

£900 is way too high for me to consider paying, that would be a sizable chunk of the value of the entire car, especially considering the problem isnt getting worse.

Has the problem only recently started to happen of did you buy the car like that?

Would it be worth drawing the attention of Lexus UK to this thread?

I've been thinking about this a little more.

I've noticed when this problem happens the most, it's comming off the motorway to a stop, and especially after lots of hard accelaration on the motorway.

I don't get what would be described as knocking, but I do get a solid thump sometimes when cruising up the sliproad off the motorway.

It's asif there is a clutch in the drivetrain that is stuck together, and it's not disenguaging when it should, the car will judder a few times, then a loud thump and everything runs smooth again.

GS Sport, does that sound fammilar?