caddyowner

I have a 2010 HS 250h with about 3,500 miles on it as a loaner for a couple days while my new (to me) LS430 is in the shop. This is the first hybrid I've ever driven. I have a 40 mile freeway commute and the car regularly feels like it is misfiring when cruising at 75 with the cruise control on. I then noticed that the feeling of "misfiring" corresponded to the electric motor kicking on per the display on the dash. Is this feeling normal for the car or is something wrong with it?

caddyowner

An update: My asst. service manager confirmed that this sensation is normal for the car, it is caused by the electric motor turning on and off, and other drivers have commented negatively on it.

dedas1

Hi. Well, it really is true. It is a "rubber-banding" feeling as the electric motor and the engine compete for the "on" setting. Lexus has done a terrible job in smoothing this out. I have made many comments about this as well as a thread that I started before I knew what was the cause. I have spoken to the service depart and have taken a test drive with the head service dealer, and all he could say was, "This is normal for a hybrid". If you research this issue, it was also a major complaint with the RX400H. After Lexus got so many complaints about it, they finally did a firmware upgrade to even this out and it is no longer noticable. I can say this from experience, since we own a RX400H and have not sensed this at all. Therefore the surprise and dissatisfaction about the uneven wobbling on the freeway. Again, it occurs mainly around 45-50 mph and around 55-60 mph. The car computer can't seem to make up its mind. What I have found frustrating the most is when I go around on a clover leaf , merging into traffic, and the car is jerking around like crazy. Otherwise I have learned some to ease off the gas pedal when I sense the jerking, and it resolves the competing problem. The Lexus service said the only way to resolve this is to have more customers complain about it. I have begun to hear more comments about this issue as the HS becomes more available. Hopefully with all of the negative press on Toyota and its slow response, they may speed up on developing a fix for this problem.

KGenaidy

Hi dedas1,

I have never experienced what you are describing. I would like to try to duplicate it ... just to understand and "know about it".

Would you please explain the mode, amount of acceleration, using cruise control, other particulars to create this behavior.

Thanks!

caddyowner

I suspect it was present at all speeds, but I never really noticed it except when cruising on the freeway when I expected a smooth ride. Driving around town while stopping and starting, the feeling probably gets blurred into the other driving motions.

In concept, I thought the car was good for a small / medium sized person that had a short local commute, didn't need a large trunk, didn't carry adults in the rear seat, and didn't have an addiction to V8 power. On the other hand, I was glad to get my V8 LS back, spread out inside, and blast out of the dealership. I make Al Gore cry.

dedas1

Hi KGenaidy,
My suspicion is that some cars are worst than others. I have seen very few individuals repond to this sensation, but the service dealers at Lexus is aware. I even called in to complain about it to a few different service agents, one of which owns an HS. He went as far to even say his friend that was riding in the car thought he was pulsing on the gas pedal just for fun and asked him to stop doing it. He said this was a normal component of the HS.
I do not know how you do not feel it, other than, as above, perhaps some cars are more prone to it than others, or perhaps ones driving style. Your postings suggest you are a much more sophisticated hybrid driver than most. As I have suggested, accommodating to the hybrid "rubber-banding" (RB) by easing off the gas pedal has taught me to adjust to some of the more pronounced occurrences of the RB. My suggestion is to accelerate, speed up and down around 59 to 62 mph for a few miles and even hold it there for a few miles and see if you get that sensation. Similarly, it occurs around 49-52 mph. By Lexus admission, it occurs around this region and is a programing problem that yet is to be solved. Going around curves with this happening and trying to merge into traffic is hair-raising, especially with it RB more. As I said before, it takes some getting use to, since driving a Acura Legend sedan to the HS was for me, has clearly become a step down in luxury. I wish I had not sold my Legend. Anyway, you should be glad that your car does not display this behavior, or you are not sensitive to it. I even considered possibly that my car was defective, but after having the problem acknowledged by Lexus by several service individuals, I am left to the conclusion my only options are to become use to it or sell the car now. I am slowly getting use to it, but still think about the latter frequently. Enough ranting.

KGenaidy

Hi Dedas1,

What mode are you in? Does it matter what mode you are in ... or are some modes worse than others? I have noticed it becomes increasingly difficult to impossible to manage the HSD system when Normal and Power modes are being used.

When the RB'ing is happening ... what's going on w/both the instant mpg's (current MFD) and also the "Hybrid System Indicator" (Chg/Power) gauge?

I wonder if this might have to do w/the eCVT transmission adjustments to the load on the vehicle. Above 40 mph ... I find this a difficult behavior to control consistently. It sort of feels like going into and out of overdrive in an automatic transmission with overdrive. I had always assumed this was a function of the eCVT programming and load on the vehicle. Could this "sort of" describe the behavior?

When I switched to driving hybrids w/CVT's ... I found/learned I was making many more adjustments with the accelerator to maintain a speed then with my previous "normal" ICE vehicles where I would pretty much just keep the accelerator "steady" for a given speed.

caddyowner

In the car I had, the RB'ing seemed most pronounced in power mode. (I never tried it in eco mode.) The RB'ing occurred when the Hybrid System Indicator was showing power flowing from the engine to the wheel AND the power would also start flowing from the battery to the wheel.

dedas1

KGenaidy, I am not an expert on this topic or on the CVT, but your thoughts are probably correct on the load. The sensation of "overdrive" is probably as good a descripiton as the RB, which is the terminology that the dealer used. I thing Caddyowner describes it correctly. When I first started driving the car, I tried the power mode, and thought I was on a bucking bronco. I no longer use the power mode. I have not used the eco mode, since it reminds me of a very tired car, essentially powerless, so I can not comment on its reaction in this mode. Again, Lexus told me that they monitor these forums to try and predict what they need to do to accommodate better service to customers. I find that hard to believe. But, I do believe that with more customer complaints about this unease feeling of RB, they will put some time and energy into correcting this. One thing that you might be able to answer that Lexus has continued to deny, and all the literature that I have read indicates the contrary, that the HS uses the same engine and design as the hybrid Camry, Is this true or not? If so, why is there such a difference in the driving behavior and the RB effect?

KGenaidy

From what I have been able to gather ... the HS has the same HSD system as the 2009 TCH ... but not the 2010 TCH. I base this on the 2010 TCH is AT-PZEV rated while our HS is not (it's SULEV-II). It doesn't make sense to me why they did this ... other than the production roll out was before the 2010 TCH engine was ready for use.

There is a HSD mode of operation that has been labeled as "Super Highway Mode" (SHM). In the Prius and TCH it very usable and reasonably sustainable. However ... in our HS it is not very usable at all.

The following is my hypothisis "It's all in the programming":

At highway speeds the HS is always trying to find itself (so to speak) ... causing among other things the RB effect. I think Lexus changed the HSD programming to be different than the TCH ... and created a situation that is creating these problems and dissatisfying HS owners.

My personal opinion is each Mode should have a different performance profile. In hopes that Lexus might actually read this ... here they are.

Eco - very similar to a Prius/TCH in Eco mode. Has sustainable SHM mode as is geared towards the maximum fuel efficiency possible.
Normal - middle ground between Eco and Power.
Power - as much power and acceleration as is available.

Hopefully this makes at least a little bit of sense.

caddyowner

Thank you for adhering to model forum guidelines of using at least 5 unique acronyms per paragraph. Extra points for including 2 compound / hyphenated acronyms.

KGenaidy

sorry about the acronyms ... I usually try to stick to "english". But I have to admit ... at-pzev is much easier then "Advanced Technology - Partial Zero Emission Vehicle" ... or sulev-ii which is "Super-Ultra-Low-Emission Vehicle II"

herbvdh

I have never had that feeling at all in my 2004 Prius, 2006 RX400h or the HS250h loaner I had for several days and did all kinds of driving in Eco., Norm, and Power I did several hundred miles driving deliberately to see how I liked it. My lease is up on my RX400h soon might buy it out and order a Tesla or get a HS250h... then consider a Tesla at a later date.