Rx 400h Highway Surging Anyone?

[kroder]

We just picked up our new Rx 400h last week and LOVE it. That is until I drove it on a short highway trip. During which I noticed what I can only describe as "small suges" in the speed. It is almost as if you have your foot on the gas and you are ever so slighly moving your foot up and down very quickly. I at first thought it was my imagination and said nothing. The next day my wife came to me and asked me if it felt like the car was "jerking" on the highway.

I then let my brother drive it. Without telling him a thing he too noticed it. It only happens at speeds over 50mph and never with the cruise control on. I took it to the dealer and I think they thought I was crazy. They had a non-hybrid trained mechanic drive with me and he blew it off to the "nature of the hybrid" which I did not accept. They then had a hybrid trained engineer look at it and low and behold he too agreed something was "not right". He then contacted Lexus who told him this was not the first complaint on this issue. They asked to keep my vehicle for a "few days" while they fly an engineer out from Atlanta with some specific equipement to look at it first hand. In the meantime my shiny new Rx sits on the dealer lot while I drive around a new but very boring Es300 loaner car.

So, has anyone else experienced this? If not, please take your Rx400 out on the highway and see if you notice it too. I am anxiuos to find out if this is a problem with all the 400s or just a few of them!

[RX400h]

The slight surging, the feeling of slightly varying brake pressure, and the electric motor roar are all part of the hybrid experience. However, the positives far outweigh the negatives, IMO. I drove from San Diego to Monterey (many hundred of miles) and never once felt that any of those issues were unbearable or even a slight nuisance.

The biggest gripe I have is that I can't open the tailgate all the way in my garage. (which is also the case with RX330 owners, I'm sure).

Overall, though, we are very happy with our RX400h, especially at the gas pump.

[kroder]

I was certainly hoping that it was indeed a simple fact of the "hybrid experience" but Lexus seems a little worried about it. They keep calling in more "specialists" and various engineers. In fact, they just called me and they want to keep it until Monday because someone else wants to run some tests on it now.

Also, as I mentioned they did tell me I am not the first to have this problem. Frankly, I am willing to put up with a little "hybrid nuance" on say a $25K Pruius, but not on a $50K Lexus. For $50K it should be close to perfect. If not, I may just drop back to an Rx330 and wait until they get all the bugs out of this model.

[tedpvhome]

I too have experienced the "surging effect". There must be a bug in the control circuit software for the throttle when going at freeway speeds. This is not acceptable for most drivers who will follow our lead in this new vehicle, I'm sure it will confuse them.

We could get technical and talk about the servo loop feedback dampening coefficient not being tuned for highway speeds, but

I prefer the experts at Lexus fix this problem.

Ted

I was certainly hoping that it was indeed a simple fact of the "hybrid experience" but Lexus seems a little worried about it. They keep calling in more "specialists" and various engineers. In fact, they just called me and they want to keep it until Monday because someone else wants to run some tests on it now.

Also, as I mentioned they did tell me I am not the first to have this problem. Frankly, I am willing to put up with a little "hybrid nuance" on say a $25K Pruius, but not on a $50K Lexus. For $50K it should be close to perfect. If not, I may just drop back to an Rx330 and wait until they get all the bugs out of this model.

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[katzjamr]

I have driven my 400h over 2400 miles and two other demo vehicles. All of them are smooth over 50 mph with or without criuse. On the freeway the ICE (internal combustion engine) seamlessly turns on and off depending on its own needs. No 'stutter'. At low speeds the cycling of the ICE is more noticable but as RX 400h says, part of the hybrid experience. I will ask this question just to make sure. All drive by wire pedals like the 400h to not function correctly if you have your left foot on the brake pedal at all and use the gas at the right. If you drive with both feet it can cause this problem. I know you have had three people duplicate this issue for you and i imagine they dont drive with both feet. Just checking. Please keep us posted with the results of the Atlanta technician.

[Philly400h]

I think I've felt this when cruising at 35-40 when really trying to really keep the ICE from turning on, however it runs smoothly all the rest of the time..

I think that's what they're referring to by "part of the hybrid experience", and it's quite rare and vague - but it sounds like yours is not as slight, and happens at a higher speed. I'm hoping they will be able to offer "upgrades" in the future as the technology gets more widespread road use, since I plan on sticking with my 400h one until at least 2 models down the line.

[patt]

We have a bit over 5000 miles on ours including a round trip from Sacramento to San Diego mostly on Highway 5 so we have had plenty of time to feel any odd highway behavior. I don't notice any surging on the freeway. Very smooth. So was the one I test drove for an hour.

[jerryray]

We have a bit over 5000 miles on ours including a round trip from Sacramento to San Diego mostly on Highway 5 so we have had plenty of time to feel any odd highway behavior. I don't notice any surging on the freeway. Very smooth. So was the one I test drove for an hour.

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I have not noticed that exact feeling at all.

BUT, I need to really floor it to get out in traffic, AND take my foot off the pedal right away, the car still accelerates for a second or so, VERY scary.

Anyone else notice this?

[RolandB]

I will have to say that all my family (includes son and wife) have experienced this 'stutter' effect and it has not been at any particular speed that I have noticed it. I will try to keep track of the speed and environment (highway, traffic, ICE/battery/combo, A/C, cruise control, etc). We have about 4600 miles on the car as of today and when I talked to my service rep, he said I could wait until the 5K service or schedule a service appointment for it specifically. I opted for the 5K and certainly hope this is NOT a 'hybrid experience' thing. I have currently a 21.58 mpg over the life and a 20.38 for the last fillup... not close to my expectations. Add in the 'stutter effect' and my praises are slight! A comparably equipped RX330 might have certainly delivered equal performance for my requirements. (I've not encountered the 0-60 in 7.3 seconds situation which would elevate my opinions... I've passed the hot-rod stage of life in my second year in college! Acceleration comes in handy for freeway on-ramps though!)

[patt]

Roland,

It is interesting that you encounter the problem plus low gas mileage. I have a feeling that the control systems on the car might sometimes be not quite smart enough. Lucca mentioned TSIB EG010-05 in a post on the RX400 Dead Battery thread. The idle speed training in the RX400 can apparently get messed up if the 12 V battery has gone dead at some point. It can cause reduced fuel economy and the engine running more frequently then normal or too long. I wonder if it wouldn't also cause the "surging" effect too as the engine goes on idling at the wrong speed. I wonder if some of the cars are coming from the factory or out of shipment needing this proceedure.

Ideally, I would hope that a control system like this would monitor itself and re-adjust, but apparently it doesn't. You might ask them to try the retraining process in TSIB when they do your service.

It definately isn't something ours does.

[skyfish400h]

Roland,

It is interesting that you encounter the problem plus low gas mileage. I have a feeling that the control systems on the car might sometimes be not quite smart enough. Lucca mentioned TSIB EG010-05 in a post on the RX400 Dead Battery thread. The idle speed training in the RX400 can apparently get messed up if the 12 V battery has gone dead at some point. It can cause reduced fuel economy and the engine running more frequently then normal or too long. I wonder if it wouldn't also cause the "surging" effect too as the engine goes on idling at the wrong speed. I wonder if some of the cars are coming from the factory or out of shipment needing this proceedure.

Ideally, I would hope that a control system like this would monitor itself and re-adjust, but apparently it doesn't. You might ask them to try the retraining process in TSIB when they do your service.

It definately isn't something ours does.

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Both my friend and I noticed difficultiy in keeping the car on a given speed coming home from the dealer when it was new. Since then (now at 2600 mi) it has calmed down so that it is not noticable, or I've just gotten used to it.

It still has the typical automatic transmission behavior when you let off the gas... coasts reaaaally well. If you want to actually slow down, you have to go for the brake. The "B" position is working better for this now that the compression has come up, so I use that in heavy traffic to keep from having to back and forth between the gas and the brake.

I too am getting 22 mpg on average and I plan to have the dealer look into this TSIB as well as tire pressure/alighnment and the windshield distortion near the top where it makes all the mountains look squished.

[av8tr]

I too noticed slight surging at freeway speeds, but it seems to have calmed down a lot since the car was brand new. My mileage has been averaging about 24.5 mpg.

[jashev]

I too noticed slight surging at freeway speeds, but it seems to have calmed down a lot since the car was brand new.  My mileage has been averaging about 24.5 mpg.

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I have also noticed a slight surge on the highway, however it is so slight, I can't tell whether it may be my foot on the gas pedal as the vehicle hits a rut or two. It doesn't appear to happen when cruise control is engaged, so I am thinking that the gas pedal may just a tad too sensitive.

[jerryray]

I too noticed slight surging at freeway speeds, but it seems to have calmed down a lot since the car was brand new.  My mileage has been averaging about 24.5 mpg.

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I have also noticed a slight surge on the highway, however it is so slight, I can't tell whether it may be my foot on the gas pedal as the vehicle hits a rut or two. It doesn't appear to happen when cruise control is engaged, so I am thinking that the gas pedal may just a tad too sensitive.

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Jashev, so how would you compare the 400h and your X5?

[speedyg]

I've felt the surging also at highway speeds. I think there was another thread about it where people seemed to be saying that tire pressure was the cause. It seems more likely to me that a gust of headwind or a slight incline triggers the electric motor to kick in to maintain speed. I could see why this would happen with cruise control on, but with cruise off it still seems to happen. I think it's a bug in the control software.

I too noticed slight surging at freeway speeds, but it seems to have calmed down a lot since the car was brand new.  My mileage has been averaging about 24.5 mpg.

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I have also noticed a slight surge on the highway, however it is so slight, I can't tell whether it may be my foot on the gas pedal as the vehicle hits a rut or two. It doesn't appear to happen when cruise control is engaged, so I am thinking that the gas pedal may just a tad too sensitive.

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[jashev]

I too noticed slight surging at freeway speeds, but it seems to have calmed down a lot since the car was brand new.  My mileage has been averaging about 24.5 mpg.

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I have also noticed a slight surge on the highway, however it is so slight, I can't tell whether it may be my foot on the gas pedal as the vehicle hits a rut or two. It doesn't appear to happen when cruise control is engaged, so I am thinking that the gas pedal may just a tad too sensitive.

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Jashev, so how would you compare the 400h and your X5?

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Great question. My wife and I stopped into the Lexus dealer on an impulse one night when we were out for dinner. I had done some research on the RX400h and wanted to check them out. I loved the feel of the car and bought one on the spot trading in my '04 Audi A8L. I was ready to buy two (one for the missus) however she wanted to try it for a week before making her decison (the X5 is really her car).

Well guess what? She drove the Lexus for a week and said there was no way she would give up her X5. It might end up really costing me because now she wants a new X5 :P .

In a nutshell, if you want a real high performance vehicle, I have to lean towards the X5. Acceleration and handling both go to the X5. I would also say that the X5 has the best AWD system I have ever seen bar none. BMW always cheats towards the rear wheel drive part of things and I like that feel better than the uncomfortable torque steering effect in the Lexus. If you stomp on the X5 it will seamlessly transfer up to 90% of the vehicles power to the rear wheels and you never feel a thing. In fact, the X5 will also transfer up to 75% of the cars power to a single wheel if the situation demands it. It's absolutely surefooted in the worst winter road conditions.

That said, I personally think the X5's steering and ride are too stiff for me. I find the Lexus much more comfortable to drive in a leisurly manner. If I want performance, I also have a BMW Z8 which is more than I could ever want. For day to day driving, the Lexus has proven itself to be reliable and economical. An imminently practical vehicle.

[RX400h]

In a nutshell, if you want a real high performance vehicle, I have to lean towards the X5.  Acceleration and handling both go to the X5. 

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Actually, according to Car & Driver, the RX400h out-accelerates even the 8-cylinder BMW X5 [6.9 seconds(RX400h) vs 7.1 seconds(X5)] and trounces it in fuel mileage (the X5 achieves only 16/22 EPA numbers). Also, as you noticed, the RX400h has a smoother, more comfortable ride. From what I've experienced, most women prefer the smoother ride over ultimate handling. We weighed fuel mileage and reliability (the Lexus RXs are Consumer Reports top picks) over handling for our SUV purchasing decision and with gas prices soaring beyond what anyone had expected even last year, we're happy we made this decision.

Still, if everyone thought the way we do...........

[jashev]

In a nutshell, if you want a real high performance vehicle, I have to lean towards the X5.  Acceleration and handling both go to the X5. 

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Actually, according to Car & Driver, the RX400h out-accelerates even the 8-cylinder BMW X5 [6.9 seconds(RX400h) vs 7.1 seconds(X5)] and trounces it in fuel mileage (the X5 achieves only 16/22 EPA numbers). Also, as you noticed, the RX400h has a smoother, more comfortable ride. From what I've experienced, most women prefer the smoother ride over ultimate handling. We weighed fuel mileage and reliability (the Lexus RXs are Consumer Reports top picks) over handling for our SUV purchasing decision and with gas prices soaring beyond what anyone had expected even last year, we're happy we made this decision.

Still, if everyone thought the way we do...........

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Like everything else in life it always depends on who you ask. At the end of this posting are the URL's for two articles (one on the X5, the other on the RX400). Based on these guys the Lexus does 0-60 in 7.2 seconds, the X5 in 7.1. I would, however comment that when you get down to tenths of a second, it no longer becomes a mechanical issue but one of how good the driver is.

We live in a fairly rural area and the X5 gets about 19 mpg around here (on premium fuel). But when you buy a BMW with a big V8, you're not really counting mpg, are you? Before the X5, my wife was driving a BMW 750 with a V12. She still tells me that she misses the great top end that the V12 had as compared with the 4.4 (she really knows how to push a vehicle ;).

There isn't a BMW I have owned over the years (and I've had quite a few) that I could honestly say I bought because of it's practical advantages. The darn cars are just way too much fun to drive. The economy may be marginal, the backseat to small (or in my Z8's case, non-existent) or any of a number of issues, but there is nothing to compare with firing one up on a clear day, hearing the perfectly tuned exhaust rumble, and pushing the car's limits on some back road somewhere.

In the meantime, as I leave the house, I will pat my Z8 on the back as I get into the RX400h for a drive into town. That should say it all :) .

http://www.automobilemag.com/reviews/suvs/0203_bmw_x5_44i/

http://www.automobilemag.com/reviews/suvs/0503_lexus_rx400h/

[RX400h]

Like everything else in life it always depends on who you ask.  At the end of this posting are the URL's for two articles (one on the X5, the other on the RX400).  Based on these guys the Lexus does 0-60 in 7.2 seconds, the X5 in 7.1.  I would, however comment that when you get down to tenths of a second, it no longer becomes a mechanical issue but one of how good the driver is.

We live in a fairly rural area and the X5 gets about 19 mpg around here (on premium fuel).  But when you buy a BMW with a big V8, you're not really counting mpg, are you?  Before the X5, my wife was driving a BMW 750 with a V12.  She still tells me that she misses the great top end that the V12 had as compared with the 4.4 (she really knows how to push a vehicle  ;).

There isn't a BMW I have owned over the years (and I've had quite a few) that I could honestly say I bought because of it's practical advantages.  The darn cars are just way too much fun to drive.  The economy may be marginal, the backseat to small (or in my Z8's case, non-existent) or any of a number of issues, but there is nothing to compare with firing one up on a clear day, hearing the perfectly tuned exhaust rumble, and pushing the car's limits on some back road somewhere.

In the meantime, as I leave the house, I will pat my Z8 on the back as I get into the RX400h for a drive into town.  That should say it all  :) .

I agree that the numbers are close, but if you want to know what the potential of a vehicle is, check with Car & Driver. They clocked the new Corvette Z06 at 0-60 MPH in 3.6 seconds :o .

If it were 10 years ago, I would agree that everyone looking at big V8 SUVs could care less about economy, but these are times of rapidly accelerating fuel costs and a significant number of new vehicle shoppers are looking at EPA figures. Personally, I would not have purchased an SUV if the 400h or Highlander hybrid were not available. Only my (previously owned) 68 Corvette has generated more comments from friends, neighbors, and strangers. The most commonly asked question at this time is "How's the gas mileage?"

Regarding your wife's thirst for power: Lexus will be coming out with an LS600h - 500HP and the economy of a six cylinder (or at least a very efficient small V8).

[kpgood]

I've felt the surging also at highway speeds.  I think there was another thread about it where people seemed to be saying that tire pressure was the cause.  It seems more likely to me that a gust of headwind or a slight incline triggers the electric motor to kick in to maintain speed.  I could see why this would happen with cruise control on, but with cruise off it still seems to happen.  I think it's a bug in the control software.

I too noticed slight surging at freeway speeds, but it seems to have calmed down a lot since the car was brand new.  My mileage has been averaging about 24.5 mpg.

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I have also noticed a slight surge on the highway, however it is so slight, I can't tell whether it may be my foot on the gas pedal as the vehicle hits a rut or two. It doesn't appear to happen when cruise control is engaged, so I am thinking that the gas pedal may just a tad too sensitive.

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I too noticed the "surging" when cruising at highway speeds. The service department asked if one of their employees could drive the car home (about 35 miles, one way) that night to feel the experience. The next morning the Service Advisor called stating the mechanic also complained of the surging. They elected to call an expert in LA. After four additional days in the shop, I was called to collect the car. The service note states "all measured systems performed to specifcation". I pointed out that the measurements were taken when the car was stationary in the maintenance shop. The reply, summarized, stated "We felt it, could not find it, can not figure it out, so IT is not a problem." Strangely, I felt as if I were dealing with a Chevy dealership and not the pride of customer service Lexus claims.

[katzjamr]

I feel grateful that for whatever reason my 400h has been smooth at all speeds. I think it takes two to tango, and if Lexus wants to respond by ignoring the issue, i would take it in five times for the same problem, or how ever many you need in your state and invoke the lemon law. There are people who have reported that the surging/jerkiness improves with miles, or they get used to it, and they used a higher octane gas, i dont know if you have tried that. I personally feel these should run on a good quality regular... .. .