Acceleration lag after hard braking

[colacola]

2019 LC 200 w/ 60,000 miles. Wondering if anyone has similar symptom or any ideas on what to target - or tell me Im over-thinking it…...

After hard braking, immediate acceleration attempts seem to lag 1/2-1 seconds compared to normal great acceleration from stoplights etc. Regular idle and “already driving” acceleration are all fine. The lag does not have rpm increase during the lag, rather pushing the pedal results in nothing….kind of like turbo-lag I had on some turbo cars, & then comes through strong. The symptom may not be new, rather I have just noticed it as hard braking and then needing to get on it, are not something I do often. I thought maybe I got some crap gasoline so with less than 1/4 tank left I filled up on way home with 93 octane, then tonight I cleaned MAF sensor and throttle body, air filter is clean (replaced at every oil change) - just test drove again & symptom is still present after hard braking.

 

[04UZJ100]

Sounds like a typical delay in downshifting.

 

[colacola]

Sounds like a typical delay in downshifting.

Thank you

 

[rockymtn]

Yes, mine is like that and it isn't unique to the LC. My wife's old RX, her new Volvo, my old F-150 (with turbos), my old Land Rover. All 'modern-ish' cars I've owned seem to act like this, I'm assuming its a 'feature' to prevent drivetrain damage.

 

[TeCKis300]

Sounds like a typical delay in downshifting.

I agree this has a lot to do with it as modern engine control units (ECU) are more closely integrated with transmission control units (TCU). Probably related to the mechanical sequence of a solenoid switch, building line pressure, to then effect a downshift in the tranny. The ECU delays the onset of power for smoothness and durability of the transmission clutch packs.

2019 LC 200 w/ 60,000 miles. Wondering if anyone has similar symptom or any ideas on what to target - or tell me Im over-thinking it…...

After hard braking, immediate acceleration attempts seem to lag 1/2-1 seconds compared to normal great acceleration from stoplights etc. Regular idle and “already driving” acceleration are all fine. The lag does not have rpm increase during the lag, rather pushing the pedal results in nothing….kind of like turbo-lag I had on some turbo cars, & then comes through strong. The symptom may not be new, rather I have just noticed it as hard braking and then needing to get on it, are not something I do often. I thought maybe I got some crap gasoline so with less than 1/4 tank left I filled up on way home with 93 octane, then tonight I cleaned MAF sensor and throttle body, air filter is clean (replaced at every oil change) - just test drove again & symptom is still present after hard braking.

I don't believe anything is wrong. This can be tested by using sport mode and downshifting to the appropriate gear prior to braking and accelerating. I think you'll find it much more responsive.

I use to autocross different cars where response is key. My preference is manuals, but manually pre-selecting gears in an auto helps a lot.

 

[CharlieS]

May be worth evaluating your driving style.

 

[colacola]

May be worth evaluating your driving style.

Brilliant. I stated it was infrequent but the requirement arises.

 

[colacola]

Yes, mine is like that and it isn't unique to the LC. My wife's old RX, her new Volvo, my old F-150 (with turbos), my old Land Rover. All 'modern-ish' cars I've owned seem to act like this, I'm assuming its a 'feature' to prevent drivetrain damage.

Thanks for the info

 

[colacola]

I agree this has a lot to do with it as modern engine control units (ECU) are more closely integrated with transmission control units (TCU). Probably related to the mechanical sequence of a solenoid switch, building line pressure, to then effect a downshift in the tranny. The ECU delays the onset of power for smoothness and durability of the transmission clutch packs.



I don't believe anything is wrong. This can be tested by using sport mode and downshifting to the appropriate gear prior to braking and accelerating. I think you'll find it much more responsive.

I use to autocross different cars where response is key. My preference is manuals, but manually pre-selecting gears in an auto helps a lot.

Thank you

 

[Sandroad]

I agree this has a lot to do with it as modern engine control units (ECU) are more closely integrated with transmission control units (TCU). Probably related to the mechanical sequence of a solenoid switch, building line pressure, to then effect a downshift in the tranny. The ECU delays the onset of power for smoothness and durability of the transmission clutch packs.



I don't believe anything is wrong. This can be tested by using sport mode and downshifting to the appropriate gear prior to braking and accelerating. I think you'll find it much more responsive.

I use to autocross different cars where response is key. My preference is manuals, but manually pre-selecting gears in an auto helps a lot.

On my LC, I can’t select a specific gear, I can only select the highest gear it will shift to.

 

[TeCKis300]

On my LC, I can’t select a specific gear, I can only select the highest gear it will shift to.

Yes, that's how Toyota autos have worked. It's functionally the same as selecting a gear when constraining to lower gears. Until slowing down further or coming to a stop. A lazy mans manual if you will. What you can't do with this strategy is bog the engine which is a good thing.

 

[UPR LC]

Complete conjecture here, but I thought I remember Toyota reprogramming computers to delay response to accelerator input immediately after or in concurrence with brake pedal application. This was in response to the prius un-intended acceleration complaints that made national news some years ago. In addition to Toyota sawing off your go pedal so floor mats would not jam your pedal. The computer programming would cut power to the engine if you hit both pedals at the same time, and likely there is a lag in the response of the program if you go immediately from brake to gas hard. I know it happens to me at slow speeds if I stop at a stop sign and then hit the accelerator pedal quicker than normal, in this case the transmission should not need to change gears substantially (should be in 1 or 2 coming to the stop).

 

[colacola]

Complete conjecture here, but I thought I remember Toyota reprogramming computers to delay response to accelerator input immediately after or in concurrence with brake pedal application. This was in response to the prius un-intended acceleration complaints that made national news some years ago. In addition to Toyota sawing off your go pedal so floor mats would not jam your pedal. The computer programming would cut power to the engine if you hit both pedals at the same time, and likely there is a lag in the response of the program if you go immediately from brake to gas hard. I know it happens to me at slow speeds if I stop at a stop sign and then hit the accelerator pedal quicker than normal, in this case the transmission should not need to change gears substantially (should be in 1 or 2 coming to the stop).

Thanks