Runs11s

Desalve, your condition is normal. Not very likeable, but definitely normal if in touring mode from my experience in my own M7 C7.

Higgs Boson

it has nothing to do with being too rich or too lean. the mixture does not change when you switch to track mode. the ECM demands more power from a lower throttle position.

I am quite sure people changed jets and metering rods and twisted distributors and flipped air lids and even tightened throttle cable slack in the 60s. today you do the same work on your laptop to adjust mixture, timing, and, yes, throttle cable slack.....in the form of Driver Demand manipulation.

nothing to cry or be concerned about. just adjust it like the true car guy you/we are/were.

furiousox

Forgive my noobness, but is this due to the car being in 4 cyl mode? Or does this happen even when it's in v8 mode?

*C7*

I would really like to fix it but I'm not going to chance voiding the warranty.

*C7*

We are talking full V8 mode.

Higgs Boson

then I guess you better give it a little more gas as you release the clutch pedal.

mjw930

I just wish you could select throttle response the same way you can lock in steering effort.

I will, however, probably get a Diablo just for its ability to adjust things like this. They also claim once removed its undetectable by GM's dealer tech system. Not sure I believe that but I know for sure systems like HP Tuners are detectable.

Chevy Cust Svc

Desalve,

I realize how displeasing it can be when faced with an off-idle throttle concern like this, and though you're seeking thoughts and opinions, I would be happy to communicate this situation with the designated Customer Experience Manager at your preferred dealer if you feel an official diagnosis is necessary. Feel free to message us privately if you'd like to proceed, or discuss this situation further.

William R.
Chevrolet Customer Care

Desalve

Been while since I've posted on this issue. I have been diligently attempting to find the real story. After a lot of guys on this site tried to tell me I didn't know how to drive the car I finally got the real scoop from a real Bow Tie Guy:
Dennis,

It was a pleasure to speak with you at the US Nationals. I have spoken to some of our calibration folks and the off throttle launch sag that you described is documented. It is something in the software set in the manual application only. He tells that the software guys are aware of it but at this time, there is no indication of when or if a fix will be available.



If I hear anymore, I will let you know. Sorry I do not have any better answers.



Thanks,

Blake Nye

Chevy Performance


As you can read there is a real problem with the ECM's on the stick cars.
Case is closed

Pete43

If I hear anymore, I will let you know. Sorry I do not have any better answers.

Blake Nye

Chevy Performance


Thanks for the info! My C7 M7 has the throttle lag too. I drive it in sport mode 99% of the time. I think I will get a tune after the warranty runs out. It does a lot of strange stuff while decellerating too. I guess its emissions related.

First Z06

I have a '15 Z51 MN7 with less than 200 miles. It has the same sucking noise as Desalve's Vette and others. Since it has such low miles I have not been tearing around town and have not noticed any deteriorated performance to date. I had wondered about the noise though. I have owned 2 other C6 Vetts. Both manual trans versions, one a regular coupe and the second a Z06. Neither one had an instant of throttle lag. They were ready immediately with full power NOW!! Keep me in the loop via PM's if GM comes up with a remedy. It is just an annoyance at this time. (Love the car.)

JoesC5

Probably something to do with emissions. My Z06 would hesitate slightly, and some times bog for a split second on an easy start in first gear, with very little throttle application. After I had new PRC265 aftermarket heads installed, and the shop had to redo the factory tune because of the increased airflow, the problem was corrected.

7thgeneration

Hill assist is for those who can't really drive a stick. Nuff said.

#1c6

i have the same issue with the lag, i was wondering if the DiabloTune would take care of that problem?

Desalve

The problem is more than a nuisance. It goes to the heart of drivability. The car is a terrific performer when you want to drive that way but when you need to tame it, city driving, it is difficult to drive. Especially in a condition when you have to prevent a roll back into a car stopped behind you. It is impossible to catch the car with the clutch when you quickly move your foot from brake to throttle. You simply don't have any engine power. And yes the "hill assist" is not active. When at BG for the caravan celebration I spoke to Harlan Charles about the problem. He indicated no awareness of it and after some discussion his solution was to use the emergency brake to hold the car and get some revs up to engage the clutch then the brake would release automatically. Good grief I pay over $70K for a car that I can't pull off a minor hill without a stall!

lancekl

William,
This is not an isolated issue, it is common to all the manual transmission C7s.
Instead of dealing with isolated customers, find out what or if GM plans on doing about it. Probably a simple software change if they are inclined to provide some customer service.
Thanks
Lance

Larry/car

Hill hold cannot be turned off so we live with it. Definitely needs improved. Wonder if anything has been reprogramed on the 2015's hill hold.

ST8GS

I hear a "whoosh" sound in my manual C7 but have not noticed a real lag when accelerating from a stop in slow conditions. Or any time you "blip" the throttle it can be heard. I do keep mine in sport most of the time, using tour or eco only on the interstate. I thought the sound was due to direct injection, and my dealer as well as Harlen Charles (at the Caravan) said the same.

rponfick

I realize most of this discussion has been related to the manual transmission. I have the auto and I am also disappointed with the off-idle response. It is embarrassing. I know some have stated that in the Track Mode things are better, but how many want to drive on the street in the Track Mode.

Maybe we could get GM to offer a "double pumper" carb. option.

Ralph

JoesC5

I don't realize how much throttle lag there is in my Z06 until I drive either my 56 or 64 and blip the throttle and see an instant response in engine RPM.