ChuH

Have now 1800 miles on the RC-F. A couple issues I have notice that is a little annoying. Just want to see if others have the same issues. Most of driving is on normal mode city driving. On occasional Sport+ mode driving (I don't notice the issues as the rpms are kept high).

1) On several occasion I tried to pass slower cars and the transmission takes about a second to down shift. Car feels it hesitate for a second or two then it takes off. (this happens in normal and sports mode)

2) Coming to a stop light from anything above 35mph and light brake pressure auto downshifting from 6 to 5 jerks. On other downshifts from other gears it is fine and smooth.

I recall seeing a youtube reviewer saying complaining about the slow downshifts. Wonder if Lexus will be updating the engine/transmission firmware. Going to ask the service manager when I do the 5K service.

Chu...

dannyk8232

Does it shift lightning quick in Sport(+) and manual mode?

NickZ

I started a thread about the same issue, it still happens from time to time, and I don't think it's the transmission as I can replicate it by taking my foot off of the accelerator for a bit and then trying to accelerate again. It feels like the engine starves for fuel for a bit and then gets going again. A few of the guys here think it could be due to the Atkinson Cycle switching over. I was able to show this happen to the tech when he went for a test drive with me, he said they would contact Lexus to see if there is anything that has been posted by corporate yet.

I don't have the harsh downshift that you are experiencing, but I do think we are both experiencing the same hesitation issue.

dannyk8232

I've heard that in auto mode the ECU learns your habits over time and responds accordingly....so if you never mash the gas, then it may lag a little the first time you do. But I have no firsthand knowledge because it's so fun driving in M/Sport mode (ISF) once the oil warms up.

I'm certain experts will chime in once they see your post

DougHII

Been discussing this issue. Too many gears and seems like it goes into very high gears quickly in normal manual mode resulting in a pause when the tranny tries to skip a bunch of gears on an aggressive down shift.

I solved this by driving in Sports + and mostly in manual mode. There is no pause and the engine sounds better. Win, win.

Definitely ask your service manager. I am going to press the issue when I go in for my 5,000 mile service. They could easy remap the tranny to make a noticeable improvement in several respects.

DougHII

I would think a fuel pressure issue would trip a check engine light.

I know what you guys are talking about and I noticed it also in normal auto mode. Complained about right after purchase,, I noticed the pause again a couple of days ago when I drove in normal auto for the first time in a while.

I have dealt with remaps on both Porsche PDK and BMW SMG. Amazing what little soft ware tweeks can do. I thought my SMG was going south when it was just a software issue.

ChuH

Never notice it in Sports+ as the rpm are kept high in this mode. Rarely use manual mode. Mostly city driving as the speed limit here on Guam is only 35mph. Occassionally would break the law and go above that . Wish we have a highway here.

ChuH

Can't always reproduce the harsh downshifts between 6-5 therefore would be very hard for tech to troubleshoot this issue.

aWorkOfArt

Hey there Chu!

Ive had the same issues when it comes to passing cars, the car stales for a second then takes off in Auto Normal mode, but I dont notice this when in Auto Sport or Sport+. I am guessing its the ECU's reaction time to the pressing of the pedal that is the delay? I fix this by flicking down shift twice to get into a lower gear and then make my move.

I have yet to experience the harsh down shifting that you are describing in Auto Normal but I did however notice the slightly harsh down shifts when in Auto Sport and Sport+... my guess for that is, because Race Car.

Gonna be heading outta work in a few and report back if I come across the harsh down shifts from 6-5

aWorkOfArt

Update:
Just got home and sorry Chu I cant replicate what you mentioned. Normal driving in traffic and outside temp was 90... Not sure what may be the problem bro...

ISF001

This is correct, but no "expert" here.

The ECU will "learn" your driving habits. If you want the car to be more responsive to throttle input, work the gears and get on it.

I am heading towards 900 miles. At around 800, as was the case with my 2012 ISF, I noticed a marked change in responsiveness. As a point of comparison to my traded ISF, the new transmission is superior, particularly more responsive to and faster on downshifts, which was one of my gripes with the first generation 8-speed tranny.

To ensure you do not have a tranny issue (which I doubt based on what I am reading), consider these points.

1. The car is obviously far from quickly responsive in the ECO mode.

2. The normal setting desensitizes the throttle, so here to do not expect rapid response.

3. In Sport, you should have quick response, but don't expect gears to hold their position for a long time. It will downshift when you slow the car, and acceleration is less linear. Steering is more direct. I drive in the Sport mode in town.

4. In Sport+, the RCF programming aggressively holds gears and runs down through them based on throttle inputs and speed on the straights and corners. You should not receive many downshift refusals, if any, and downshifts will occur in .2 seconds. You can intervene using the paddles or shifter, but AI will rule in this mode. Each gear will be held until at least 4,000 rpm. If you kick the beast in this mode, it WILL drop the hammer and give you what its got. The transition should be from Dr. Jekyll to Mr. Hyde. It's essentially a race mode.

5. Manual is a blast. Depending up how much throttle you are applying, the shifts can range from smooth to high aggressive deliveries with a kick upon each upshift--much like my 2012 ISF did. You will experience full torque-converter lock-up from second to eighth gears for clutchless manual shifting. You may even experience violent gear shifts or strong kicks, depending upon your speed. Upshifts are executed in 0.1-second in M mode, with the transmission’s throttle blipping control matching the engine speed to the gear.

6. Expert--I have not gone there yet. Traction control is off and VSC is reduced yet available to prevent you from doing a complete spin if you turn the car 90 degrees (on a track). If you want to burn the 275/35s, this is the mode.

If you want to have more control in traffic, engage the Sport setting, work the gears, and this RCF will show you its stuff.

The rest of this is up to the driver, and this car takes some time and patience to master. The RCF likes to rev, so adjust your style of driving accordingly to unleash the best from the car.

At even rocketing speeds, the RCF is incredibly responsive, stable, and confidence inspiring. I am coming to understand this car.

rjmalm

ISF001
Thanks for your summary, it will be helpful for my break in miles.

Carnevino

I've noticed this as well guys. I have around a 10 mile commute before I hit my first red light and turn/merge lane onto another road. If you hit the light just right then there's no traffic traveling the direction I'm merging into.....good place to try and replicate this "shifting" dilemma. Merging in "Normal" mode I can get the car to exhibit the symptoms we're talking about. I get the same results in "Sport" auto mode as well. So yesterday I had a little bit of time to kill so I took the RC f back out and tried the same merge in "Sport+" M mode. I kept my race line/brake line nice and straight then hit the apex properly with a nice clean track out...car ate it up perfectly. This car definitely enjoys it more when the driver keeps the RPM's up....but it seems it needs a tweak with something like you guys are discussing on here. I'm with Doug about a simple flash can fix this. I'm also with Art about the G meter could possibly be a culprit at play here. I DO notice a slight hesitation when tracking out of a turn in "Normal" mode and try to get on it....just so slight, but it's there. To be fair, I haven't tried taking the merge in "Sport" or "Normal" modes in the "M" position and just using the paddles. I'll try and do that soon.

Eddiegee

Has anyone else had this rough downshifting issue? I noticed when coming to a stop from over 40mph at about 8-10mph the car slightly jerks when downshifting in normal mode. Feels sorta clunky. Any thoughts?

USBGSF16

GET A TSB FLASH, GET A INTAKE AND EXHAUST, GET A APEXI THORTTE CONTROLLER . Then no more slow shifting