We bought a certified 2020 RX-350 from the local Lexus dealer about two years ago, with almost exactly 40,000 miles on it. It was pristine and exceeded all of our expectations in almost every way.

I did a surface search on the threads but couldn't find these topics, so here goes;
1) The throttle is VERY aggressive! The slightest pedal movement from a standing stop may chirp the tires on a warm street and if its raining, the risk of spinning the tires from a stop is always there. It feels like there is a gap between the pedal and the engine. I know its a drive by wire system, so visualize a dead spot in the pedal switch resistor.
2) Couple that with the transmission shifting 1-2-3 gear as the car crosses an intersection, then back to 2nd gear as it accelerates. I cant help but think there's a connection between the two issues. It shifts way to early in my opinion, I think it should hold the gears a bit longer.

As a comparison, my son has a 2020 ES-350 (same engine, probably the same trans too) and its flawless. My former 2016 ES-350 didn't exhibit this problem either.
The dealer drove it and couldn't recommend anything since there are no faults stored in the computer and no active TSB's. I have sort of lost confidence in their willingness to resolve these issues. I'm not in a position to toss them a blank check to experiment with parts swapping or experimental programming.

These issues are not deal breakers and only a bit frustrating. We have driven the car another 30,000 miles since then.

 

The throttle response chances with each driving mode. Switch the transmission selector to economy and see if you notice a difference. If this doesn’t satisfy you, make sure the latest transmission software is installed.

 

Try pulling the POS battery cable off for about a minute to clear the memory of the ECU. That brings everything to factory specs, then the car will relearn your driving habits.

 

When I was playing with the Eco-Normal-Sport switch in my 2024 ES350, I decided I did not like the eager response to the accelerator pedal in the N and S modes. It did seem to want jump forward with a light touch on the pedal. My driving, mostly city, is most comfortable with the Eco setting. I can still floor it going down an Interstate on-ramp and be going 70 or more in time to merge, so Eco does not prevent rapid acceleration when wanted.

 

You never mentioned if the throttle problem was there when you first bought the car. Sensors can be very touchy and there are two working together here. You have the gas pedal sensor and the sensor connected to the throttle servo motor. It could also be the mass air flow sensor, vacuum leak, gas pedal adjustment, or 20 other things. There should be a fault stored. Take it to a Toyota dealer and see what they say. Since this seems to be a rare problem, dealerships don't want to use a lot of time trying to figure it out. It costs them money.

 

To further clarify, they problem was there when I bought the car from the Lexus dealer. This is one of the pitfalls when you buy a car online without actually physically test-driving the car(s). I did drive it before I signed the title transfer and commented on the throttle but a 15 minute check by the service advisor said it was normal.

There are no codes stored, either pending, live, or historic. One person asked if it was like an old car with a bad accelerator pump. Its more like 90% of performance in the first 5% of throttle movement, very aggressive.

Like I said, its not a deal breaker, just a slight annoyance. My wife is the primary driver and she says she has gotten used to it. Also, the local Toyota dealer wont look at the car except for customer pay service(!) even though its practically the same as the Highlander.

 

I recall when I purchase 2000 RX300, my wife complained about gas pedal being too light. Service also said it is normal, so we decided to wait and see. Couple of month later she did not even remember that was an issue.

 

Is yours a FWD or an AWD?

How much throttle in terms of % is consider slightest?

Mines have less miles than yours and it doesn't chirp tires.

Also are your tires worn?

 

I have the same problem. Last year I purchased this certified vehicle with only 15k miles on it. The dealer said everything is normal and there were no codes found. They suggested to use 93 octane gasoline, but that did not correct the issue. It would be nice if they come up with a solution for you. If so, please share!!!

 

As I stated, I feel like its a VERY minimal throttle/pedal position movement. My tires are almost new major brand, and front wheel drive. For example, its very difficult moving away from a stopped position without a jerk, not neck snapping but far more than any other car I have or have had (four other Lexus products, more than a half-dozen Ford products, and a couple of Infinitis) in the last 30+ years of driving. On certain streets, I can hear a tire slip and if its raining or a wet street, a tire slip is almost guaranteed.

Its hard to quantify how much movement of the pedal I press but I assure you that it is minimal.

As an engineer with considerable automotive experience, albeit with no access to the inner workings of the PCM, its puzzling. To get one more step technical, if any of these readers are familiar with an electrical POT, visualize a dead spot in the coil where the arm moves from one section to the other. Or a resistor that is connected to a lever, where the lever arm requires minimal movement to actuate the resistor.

 

Ok. In that case we can get technical.

The Accelerator Pedal Position Sensor and the Throttle Position Sensor (integrated to the throttle motor) has a potentiometer. These sensors are the one that sends the signal to the PCM to know how much throttle is being demanded. You would need to confirm if the resistor inside is working properly. You can easily do that with a generic scan tool by looking at live data and slowly depressing the accelerator pedal. On the other hand, do you have anything connected to the Accelerator Pedal Position Sensor, such as a throttle commander? This modifies the signal telling the PCM the throttle demand is higher than normal.

Looks like we've got a few Engineers on this board.

 

Being a retired engineer is indeed a blessing, or a curse! In this case, both...
Before the days of scantools, my seat of the pants feeling would be a defective throttle actuator at the pedal and possibly the TPS sensor at the throttlebody. Since there are no codes, the dealer is reluctant to chase the rabbit unless I open my wallet, and I'm too tight to open that door!
My son as a throttle commander on his Raptor and it totally changed the trucks driving attitude, and would almost exactly replicate what I am experiencing here, and no, I dont have one installed.
I have access to a scan tool and might dig into it to look at the commanded voltage and throttle opening ratio in degrees of rotation per second. It will have to wait for a couple of weeks before I can do this.
Welcoming all thoughts and suggestions, thanks!