NickZ

Hey guys, just curious to see if any of you are experiencing hesitation when trying to accelerate after letting off the throttle. I typically feel it after making a turn, or when taking my foot off of the accelerator and then trying to accelerate again. I've noticed it in normal mode as well as sport, and it can bog down noticeably at times.

I thought it could be the fuel the dealership put it in when I picked it up, but I am now on my third tank of fuel (93 Premium) and it still does it. I noticed a few guys mention they had fuel pump problems, for those of you that had the pump replaced, did you notice the hesitation before the pump was replaced?

ISF001

Sounds like a pump. My RCF rockets out and the throttle is quite repaonsive.

jmcc09

I had the same issue but I believe is the gyrostabilizer that car used to determine when you are turning that make the transmission stay in a higher gear, I noticed that as I drove around and switch the display to show me what gear i was on I could see that after a turn or bump i would stay at a higher gear which causes a bit if hesitation, then again I'm not an engineer so I honestly couldn't tell you more than my opinion

NickZ

That is the direction I am leaning in, it totally feels like it starves for fuel for a few and then accelerates normally. Of course, it wouldn't do it when I tried to show the tech what was happening, and I didn't want to leave it with them at the time. It only seems to happen at lower road and engine speeds though, in the upper rev range it has tons of power and never hesitates.

It does make a sound like a bad power steering pump (I can't come up with a better analogy) at slow speeds, so I'm wondering if that's actually the fuel pump making the whining noise?

Isfast

iTrader: (13)

The same thing happens to me as well. I can duplicate it in a straight line as well. Not sure if it i the fuel pump as It does not happen if i shift manually.

kareemRCF

I know what you mean, definitely not the fuel pump.

I think it happens when you are in low speeds and high gears and you want to accelerate, what actually happens is the transmission shifting down 5 times from 8th to 2nd. That's the hesitation.

Disappears with the sport S + because you never hit more than 6th in auto mode.

NickZ

I can duplicate it in a straight line as well, I have not tried shifting it manually though. It seems to happen when it is in a higher gear and low engine speeds and I "roll" into the throttle instead of hitting it and calling for a multiple gear downshift. It's aggravating to say the least.

NickZ

It is in higher gears and low road/engine speeds but I don't think I has anything to do with the trans as I'm not flooring it and asking for a downshift. It really feels like the engine starves for fuel for a bit or the engine computer gets confused.

7No

iTrader: (1)

Try various gears at various rpms in Manual mode,i.e, try 3 rd, 4th and 5th at 3000, 4000 and 5000 rpm. Try to roll the throttle on exactly the sam each time. Then you'll have something more than just seat-of-the-pants in one of two situations to be able to make a judgement with. Then, if you want, go back and try again in sport or sport plus.

Ryanmcd

It's coming off of the atkinson map is my guess, it never does this is you are driving hard right?

NickZ

That's something I thought of as well, as its more noticeable in standard mode where eco/Atkinson would be at play. It just seems odd that it would bog down like that, it definitely does not feel normal and I'm pretty sure something is wrong. I never notice it in the upper rev range when driving hard, it happens down low on the tach when driving in traffic.

jkeifer3

I notice that the engine RPM is held "high" for a few seconds after abruptly letting off the gas. If I reapply the gas during this time I feel a "lag".

DougHII

Lol, it sounds as if it is just the auto tranny. If you want crisper more responsive downshifts, take the dang thing out of normal or use manual. Candidly, I found (and pasted on here after owning less than a week) that this auto 8 speed tranny is too sluggish on the down shift in normal and sports modes.

The solution until Lexus remaps which should should presumably be easy fix . . . drive in Sports Plus or use manual shifters in Sports or Sports Plus so this 8 speed automatic tranny is not having to kick down multiple gears immediately. Take it out of normal if you a sporty more responsive feel.

Love the RC F for what it is, but after being used to Porsche pdk, Ferrari F1, sequential and etc., the RC F is not as crisp and responsive as one would expect in a sports car with 467 hp.

ISF001

My RCF is giving me immediate and faster downshifts--much less resistance than my ISF. Overall, my experience to date is that the tranny has been improved.

Put the car in Sport +, Track (TVD), and Expert (shut off the nannies). The faster you move, the faster it responds--based on my first 500 miles. Try both auto and manual.

The tranny will hit hard under full attack and even kick in manual. Flick the paddle quickly, and you'll get quick up shifts--bam, bam, etc. Don't back off the pedal.

At slow speeds and low revs, expect comparable responses from the tranny. If you driving slow an not attending to gear shifts, you can pull back and hold the paddle. It will drop as many as 3 gears in a clip, depending on you speed. Get on the beast, and it will even kick.

Also, I find that if I set my heel into the base of the accelerator for full contact, there is an improved response on acceleration.

If your car is overall sluggish, you have a problem requiring service. I can smoke this thing up and down the road--no power delivery issues here.

If there is a chance that you added tainted few to your car, the fuel system is going to need flushing by Lexus. I had this happen years ago, and it was a problem until the fuel system was thoroughly flushed.

followtheF

I'm not really noticing any lag (except maybe for a split second when hitting the throttle on the freeway in normal mode and the tranny has to drop from 8th to 4th or something, but that's fine), but I was playing around with manual mode the other day, and it wasn't changing more than one gear at a time when I held the paddle. I know a few people have mentioned it so I was just curious, is there a trick to this I'm missing (certain conditions, settings, modes, etc?). One time I tried it on the freeway, in 8th, held the paddle and all I would get is 7th. Tried it again, just 6th. I would think if I'm cruising, I could multi-downshift into 5th or something to "prime" the motor to accelerate.

Thanks.