I love my new NX200t (especially the LED headlights!), but I'm having a little trouble getting used to the throttle. I have noticed a slight hesitation when I go back to the throttle after slowing a little. For example, when I slow to take a corner, then accelerate out of the turn it feels like it cuts off the fuel for a fraction of a second. It also happens when you have to slow for traffic or something, then start to come back up to speed. It's worse at lower engine speeds, and I can minimize it by downshifting to keep the RPMs up a bit, but it makes it very difficult to be smooth. It does NOT happen when starting from a stop. At first I thought it was a function of the turbo, and thought I would eventually get used to managing it. I've driven a LOT of turbocharged cars, and once you figure them out you can minimize things like turbo lag, but that's not what this is. This is more like a cough before the engine speed starts to come back up, which is already a bit slow due (I presume) to the lag. Personally, I think it's a throttle mapping issue where it doesn't dump enough fuel on initial throttle, and Lexus will give me the standard "working as designed" response.

i was going to wait for the first service and ask if they could look at it, but I don't put many miles on it and I don't want to wait. If others have noticed this, I'll learn to live with it, but if it's only mine I think I'll take it in. Any ideas?

 

Do you have Eco mode on? Not just the Eco drive mode, but the extra Eco option within the normal and sport drives.

 

Great question, but no. Actually, I've not had it in Eco mode at all, but it does the same thing in sport mode.

 

Maybe try a different brand or station for premium gas. My '15 does not have a throttle hesitation.

 

I've had this happen occasionally with several (non Lexus) cars. It's pretty random and hard to pin down.

 

In that case, I would suspect that the transmission is searching for the proper gear.

 

What "extra" eco option are your referring to?

 

Yes. And it's as designed.

It's the traction control/VSC aggressively kicking in based on steering angle, body roll, traction, and most importantly throttle input. The greater the latter, the more you feel the power being held back until the computer determines it's "safe" enough to release more power. That's why you feel the cut then lurch. I minimize this effect by easing into the throttle, or disengaging the traction control if I safely can.

 

When you are scrolling through the display in the instrument panel with your steering wheel controls. There is an option to for the car to kick it to ECO during normal and sport modes whenever the car feels it can.

 

Just a light, can be enabled or disabled, from the manual:
Eco Driving Indicator Light
During Eco-friendly acceleration (Eco driving),
the Eco Driving Indicator Light will turn
on. When the acceleration exceeds the Zone
of Eco driving, or when the vehicle is stopped,
the light turns off.

 

I'm old school. I assumed the whole Eco Monitor process is just a higher tech version of the old manifold pressure gauge. When you accelerate, you increase the vacuum ("increase the vacuum' sounds like an oxymoron ) in the intake manifold, and it tells you you're not being efficient with the gas pedal. On Lexus hybrids the light comes on when the ICE turns off using the Stop/Start technology.

I evaluated the value of maximum fuel efficiency against being flipped off or shot at by the people that are waiting for me to go, and decided to turn off the Eco light

 

You're right. I just reread the manual again for the indicator.

 

I was in Colorado a couple of weeks ago and noticed a definite hesitation similar to what you are describing. In my case, I felt it was turbo lag. I live in Texas at about 700' elevation and do not feel the hesitation or turbo lag here, it was only at the 5000' to 6000' elevations of Co. There was no "cough" to the hesitation, that sounds like a possible defect. What grade fuel are you using? I only use premium, using regular may contribute to what you are experiencing.

 

I think it's mostly due to a small 4 cyl turbo engine, outdated 6 speed automatic transmission combo. First turn off the traction control. I find it useless when driving a FWD, underpowered act like the NX. So the inside front wheels spins a little, let it, feather the throttle a little and drive on. You can also put eh car in manual mode and use the paddle shifters to keep it in 3rd or 4th gear