bobys

I just purchased an l/certified 2013 RX 350 (34K miles) this past weekend. I did not notice these issues on my test drive. I've started to notice that when taking my foot off the gas pedal (while not resting near the break pedal) the vehicle goes through a series of easy coasts and then some resistance (as if using an engine as break on a truck with a manual t,) then returning to a smooth easy coast.

I've also noticed that when accelerating at a slow speed from stop (I'm in traffic) there is a bit of a hesitation, like turbo lag, yet this has no turbo. The lag seems to be there even if I want to accelerate aggressively.

Ideas/options, service buletins? I hate to get tied up with a dealer service department already.... "Cant duplicate," or "that is normal operation," or "Computer codes check out." Looking for reinforcing information so I don't have to take it in once a month for an unknown amount of time.

Of our three other cars (2015 Prius, 2002 Nissan Altima, and (pre-tran fail) 2002 honda odyssey) none experience anything like this.

Our household is dumping a 2002 honda odyssey for repeated transmission failures never covered with goodwill. All service was at a h dealership and manufacturer schedule was followed. I'm already sensitive to the manufacturer/dealer relationship.

Thanks.

Jerry61

Sounds like you may have dirty injectors. Find a local Amzoil dealer and get a bottle of P.I. performance from him and after one tank of gas you should be able to tell the difference.

Clutchless

Other similar products that may be easier to find are Techron Fuel System Cleaner, get the bigger bottle, or Red Line Fuel System Cleaner. Both are available at most large chain auto parts stores.
Part of your deceleration issue is just the transmission downshifting as you slow down.

However since it is a recently purchased CPO car, I would go online to the Lexus owners site to check the dealer service history.
https://secure.drivers.lexus.com/lex...-lexus/home.do
Join and enter the VIN to see what has been done maintenance and service wise by dealers.
I would consider going right back to the dealer and complaining and maybe they will provide a free fuel system induction/cleaning service.

lexus114

or BG 44k fuel system cleaner.

fastnoypi

the hesitation is often"programmed" into the transmission computers to downshift late for optimal mpg and a less jerky ride transition.

Marqevans

There are other threads on the hesitation problem in this forum. It is most dangerous when pulling out into traffic when you need to accelerate.

bobys

Thanks for the replies. Well, I'm still on the dealer's gas. I haven't put in grocery gas to foul the injectors. Plus, to be honest, I've put grocery gas in my cars and I have not yet replaced an injector, 200K on one car and 100K on the other.

Engine break.

So, does anyone know if their RX350 is using engine break to slow the vehicle when the foot is not on the gas or break pedal (I don't use the two foot method). Mine definately has a weird thing that happens when coasting from 35+ to about 33MPH (stop and go in traffic, red lights ahead). The RPMs jump about 400RPMs. Considering the weight of this vehicle, I would not have expected to have to stiffen my neck. I would have expected this out of a lightwieght car like a fiat or corolla when shifting manually and using engine breaking, not from a 4500+ Ibs porker with an automatic. Of all the automatics I've owned, none have exhibited this.

mcdgary

My 2012 RX-350 has same symptom, and I more than once heard "Cant duplicate," or "that is normal operation," or "Computer codes check out." Finally, the Lexus Dealer suggested I take a service Tech around on a test ride. He observed my driving techniques and told me I tend to keep my right foot on the break pedal while at the same time when I initiate an acceleration, e.g., entering a primary street from a secondary one. For example coming to a "stop" (as a stop sign) and at the onset of acceleration I have not released my foot off the break pedal. The on-board computer is confused getting two inputs at that instant - a "go" and a "no go." At least this make sense, so I have tried to avoid my bad habit, and the anomaly is less frequent.

vlad_a

If you somehow press brake and gas at the same time, the ECU will put a smackdown on your acceleration, cutting all the power. Compliments of the "unintended acceleration" lawsuit(s). This will absolutely force a delay in acceleration, even after you let go of the brake.

bobys

I replied a long time ago. The website said it need to review my post. That post never showed up, I contacted the "contact us" email (from the bottom of every page) to understand what was wrong with my post and never received a reply.

I took the RX to the dealer, took someone for a drive to demonstrate the hesitation. I told them that our Prius, even with the system which takes coasting power and turns into energy can coast a lot longer and not have these odd downshifts with force at (roughly) 35 and 28 MPH.

The Lexus dealer "examined" the vehicle and the "diags" report all is well. This is odd, because I'm sure that if the car's computer recorded something wrong, it would have fired up the check engine light or some other light.

I have never been a two-footed driver with automatic vehicles. My right foot does the accelerating and breaking, each at different times. I do not straddle the right on both the acceleration pedal and the brake pedal. I can move both foots heals all the way back to the seat and the issue will still happen.

None of my prior cars, minivans, SUVs, trucks have ever exhibited this type of behavior.

I honestly would not be surprised if this vehicle would spin out if it happens on an icy road. I am not touching any pedal with my left foot and I'm not touching any pedal with my right when this happens. At the next service and the service after that, I will tell them to put that into the service record again. Next winter when it spins out, I suppose someone will sue Toyota and Lexus (they have the trained specialist which say it is fine) as well as myself. This has not be a confidence inspiring experience with Lexus/Toyota, which has detracted from my high impression of Toyota garnered from the Prius.

kitlz

bobys, your post is approved. Sorry it took so long . Please PM me if it happens again.

I can't recall another post where somebody had the same issues unfortunately. The only suggestion is to keep pestering the dealer. And let's hope there aren't any accidents. Good luck.

NateJG

You may find that the vehicle retardation is different for two conditions:

A) slowly lifting your foot off of the throttle (as in coming up upon traffic and dropping the speed by a mile or two then a mile or two, etc) vs

B) Quickly snapping your foot off of the throttle (as in "...yellow light ahead and you're going to stop soon...")

Which is very similar to

C) Quickly snapping your foot off of the throttle (as in "...now I'm going down hill and I don't need the gas to keep me at speed..." Or "...now I'm going downhill and I need to merely keep the speed I'm going...").

For "A" the engine is allowed to stay running and let the car slowly coast; while for "B" and "C" you've told the car that you want to slow down, so the engine shuts off and adds more deceleration to the car than when the engine is idling under power.

You then feel the engine restart just as you reach a point to where the engine would be stopped (like around 15 MPH) when the engine re-fires up.

If you're going downhill, the onboard computer makes decisions as to what gear would be best for the up/down grade - and may downshift earlier than previously noticed (or noticed on a level grade).

The car also knows the temperature - and takes that into the decision making process - so it's unlikely that you'd experience a spin on an icy road.

There is a thread about a fellow experiencing locked wheels resulting in him hitting a guard rail - but the General concensus of that thread is that he activated the "Hill Hold" locked brake by his erratic brake activation (all conjecture at this point).

bobys

NateJG, sorry, maybe I confused the situation. My RX is not a hybrid, so I would imagine that its engine would not shut off. Should it?

I only brought up the coasting with the Prius for comparison. Prius coasts much further, even though it is actually recapturing energy with that resistance motor linked to the wheels. My non-hybrid RX cannot recapture energy through the wheels and its engine has never shutoff while moving.

NateJG

I think you'll find that the engine does in fact shut off the fuel at times - as I tried, albeit unsuccessfully it appears, to explain. While the engine does not stop spinning, it does, for all intents and purposes, stop using fuel at times of deceleration - and it relighted the fuel/combustion process just before the engine would stop spinning (else it wouldn't be able to start without needing the starter motor).

There is a mild, but noticeable to people like you and I, difference between a spinning engine with little gasoline/ignition and one spinning with no fuel being consumed.

I suspect that you are able to tell the difference.

The car detects the attitude (is it going up or down hill?) and uses that in the decision process for gear selection.

Surely you've noticed that it hangs in a lower gear longer as you head up a hill; it also selects a lower gear just a bit earlier than perhaps you'd have expected as you let off the throttle when going down hill.

As for your other issue about hesitation - I'm at a loss (don't fully understand your observation).

And you may have noticed that I have the Prius On Steriods - and understood your comparison.

vlad_a

Engine in a non-hybrid RX does not shut off, nor features the annoying start-stop feature. To my knowledge, Toyota has not pursued cylinder deactivation for their motors either.