If this is occurring at about 35-40mph and you get on it and you feel the slump. That's what a lot of folks have complained about. Some say the flash for the fuel pump helps. This is different from the recall.

I've had this too. If your in Auto.
Some remedies is to drive in sport+ or manual. What appears to happen is that the transmission downshifts to like 3, but I think it does in this fashion to avoid the surge you would normally get.

 

 

wasn't aware that the 2015 RCF was on the airbag recall, the only recall I see for 2015 RCFs on the Lexus Recall Site is for the high pressure fuel pump.


the hesitation is a result of programming, as stated there is an LSB for it, the new ECU flash gets rid of the hesitation and the fuel pump noise that accompanies it. low voltage to the high pressure pump causes this problem. I had the flash done 2 years ago and haven't had the hesitation since.

 

 

Tell the dealer your fuel pump is making a high pitched noise when the car is warmed up and you read about this fix, it addresses the noise and the hesitation. A Lot of dealers won't do it unless you complain about the noise, so mention it.. The noise is a high pitched "whine" that appears when the vehicle is at operating temp and has been run medium to hard for awhile, it will not appear at startup usually, nor under short driving conditions, I mention this because dealerships like to say "unable to replicate" and all they do is start the car or drive it around the block. In this case it takes highway speeds and some distance to get the noise to appear. My dealer took my word for it because of how detailed I explained it.


https://www.clublexus.com/forums/rc-...u-flashed.html
https://www.clublexus.com/forums/rc-...ml#post9610511


Publication_Number: 'L-SB-0031-16'.
Vehicle Applicability: ''15-'16 RC F, 16' GS F'.
T3_ID: '16-TMS-0039-L'. Publication_Number: 'L-SB-0031-16'.


Trust me this will get rid of the hesitation, and don't let the dealer tell you it is related to the recall, it is not, it is a completely separate issue.

 

If this turns out not to be your issue, it might be how the transmission works. I've had a '15, 17, and now an 18, all have hesitated sometimes in the following situation (info estimated):

• Cruising at relatively low speed (maybe 20-35 mph) at low RPM in a higher gear
• Floor it

Car hesitates for a few counts, then downshifts. Typically can be avoided by keeping it in Sport mode or higher.

Very annoying, especially when I need to react quickly unexpectedly.

Another thing you can try is disconnect your negative battery terminal for 10 minutes, then reconnect. In theory that should wipe the ECU memory on the driving patterns the car learned. If you drove the car gently during the break-in period, might be remembering that, although I'm clear if it remembers it forever or adapts to more recent driving.

 

 

The only time I have noticed the hesitation since the flash is in eco mode with the HVAC on.

in normal, sport, sport+ with or without HVAC there is no hesitation.

I drive in eco in stop and go traffic, commuting through L.A. this is a daily thing, but I always flip to Sport once the traffic start moving above ~35mph. it has become a habit to alter the modes during my drive to work, I have city streets, stop and go freeway, then an open back road for 6+ miles, using the modes I have averaged 22mpg in my RCF, keeping it in normal or sport consistently drops it down to 19. Normal is great for city driving, eco for stop and go traffic, and sport or sport+ for highway use, I like to go into sport+ on the long sweeping interchanges as I prefer the tighter steering for those.

 

I'm totally with you man, I do the same thing. I mainly leave it in Normal mode on the freeway, but I should start putting it in Eco to get a little more mpg. But once I have room, I go straight to Sport+ in Manual mode.

 

HOLY SMOKES NORM !!
Have not heard those words in Years, Decades maybe!
Too funny (Not your issue of course) Had one of these on my old Z28 back in the early 80s. Everyone wanted one remember!
https://www.holley.com/products/fuel...s/carburetors/

Let us know what comes of your issue. Hopefully just minor fix.

 

 

With the old "Edelbrock" Manifolds too! LMAO!!!

 

Curious if anyone noticed their MPG drop after the having the TSB done? I have the hesitation and since the HP Fuel Pump recall is getting done as soon as the parts come in, was thinking of telling them about the "Noise" so they would do the TSB also. I know we don't drive the RCF for the gas mileage, but I have a sore spot with ECU reflashes ever since a dealer did one on my Diesel and significantly dropped my MPG and wouldn't restore it back to previous, so just figured I would ask.
Thanks

 

I noticed my mpg dropped a bit, like around 2 to 4 mpg after I had the ECU TSB reflashed about a year and half ago. I thought it was just my heavy foot??? And with the hesitation gone I tend to just floor it a lot!!!
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