chrismgiro

Starting a new thread for this particular issue. This was previously being discussed under the RCF Fuel Pump thread, but I think this warrants its own thread.

I own a '15 RCF with ~800 miles and have a hesitation issue, for lack of a better term. It is a drop in RPM, which causes a noticeable "jolt/hiccup" 1-2 seconds after shifting into 2nd gear at the lower rpm range (1800 - 3000 rpm). I had the Fuel Pump TSB performed last week, but the "hiccup" is still present. The throttle response was definitely improved and got rid of the "Lag" a lot of people were seeing when they romped on the throttle. The Service Tech and Service Manager both made mention of the modifications I have done and said they may be causing the issue, since messing with the intake and PCV system may throw off the ECU. I don't believe this is the case, since this is an issue with numerous RCFs, both stock vehicles and vehicles with modification, but maybe we can rule that all out even further by comparing mods and coming to our own conclusion. I have the RR Racing Titanium intake pipe with their K&N valve cover breather hose modification, The RR Racing Air-Oil Separator (The tech mentioned the PCV system has no issues in the RCF, but we all know this is not the case), and a Borla Cat-Back (secondary cat delete). I only use Shell 93 octane fuel and add mystery oil (to the fuel only). I changed my oil at 500 miles and used Mobil 1 5w-30 conventional. For the life of me I cant recall if this issue was occurring prior to all of the mods, as I did all of them around the same time and the car was so new that I may not have noticed the issue right away. Please feel free to chime in here. Hopefully we can get closer to a cause and resolution to this annoying problem.

I have attached a video of the issue, I apologize for the shadows, but I will try and get a better video and update it in this post. The issue I am referring to happens right around the 5 second mark in the video (~2300rpm after the shift into 2nd gear). You can hear the "hiccup" and see the tach needle drop.

I recently read there was a similar issue with the ISF and it turned out to be low transmission fluid causing the slipping, so this is going to be something I have the dealership check out during my next visit.

estoyf

signed - have same issue. '15 RCF with joez exhaust, ~3200 miles as of post

Phinatic

2015/1,500 miles, completely OEM. Haven't experienced anything like you've explained. In fact, I haven't had any issues; no stuck wing, brake squeal, fuel pump noise, hesitation. etc. Just fortunate to this point.

ISF001

The two of you definitely have a problem with the car. Take it in.

My carbon TV is running like a dream. The reflash made it even better and it shifts like a champion.

Carnevino

x2. Mine is running fantastic after the reflash. Take them in

JT2MA71

iTrader: (7)

I went for a drive just to try and replicate this described hesitation. Can the OP please let us know if it is seen in the video?

SmurFPwr

No mine is only in manual while slowly accelerating going from 1st to 2nd and then in 2nd gear around 1900-2400rpm is where it will drop about 150-200rpm just for a brief second
however if I'm heavy on acceleration I feel nothing and the transmission shifts and locks up solid and drives great.

estoyf

This. Car is fine under heavy acceleration. Doesn't bother me much, but for the sake of being the guinea pig, I'll drop by my dealership tomorrow on my day off and see what they have to say. I'll keep u guys posted. I'll also try a 2nd time to get them to perform the tsb for the fuel pump.

And i didn't see the issue in the video above. It's only in 2nd gear immediately after the upshift from first, under "normal" or conservative driving

estoyf

update: explained the issue to the dealer, they had a tech ride with me and the issue was replicated -- car has been in service since 10am. they provided me a loaner in the meantime. i'll updated on the fix/dealer explanation

JT2MA71

iTrader: (7)

Although I don't drive this way in manual mode, I tried doing it to see if the hesitation or lag happens. Here's a video, the only lag I noticed is the delay in actual shifting after moving the paddle.

chrismgiro

What was the outcome of this? Glad to hear the issue was reproduced and verified by the techs there.

chrismgiro

Tough to tell, but it does look like you have the hesitation after the shift into 2nd gear. The shift happens and then around the 11 second mark (looks like around 1900 rpm) in the video there is a slight rpm drop. Mine is much worse than that, though.

chrismgiro

I had the reflash done and I have the paperwork showing they did it. Is there any way for us to verify the version of code the ECU is running and if the update actually took?

chrismgiro

This is the exact issue I am referring to.

estoyf

Here is the invoice and summary of their findings. The tech rode with me and noticed the issue when I shifted into 2nd gear in manual mode. He told me trying driving in automatic and see if the issue was also present. It wasn't. I guess i really never noticed that because I almost never drive the car in automatic. Anyways, they said they couldn't find anything abnormal. It's noticeable, but not abnormal? Like i said earlier, doesn't really bother me, I just wanted to see what Lexus would find.

Does the fuel pump "recalibration" mean the tsb was done? I compared my reciept to the one that another user posted and the service writeup was different. Anyone know?