mxw1

Hi,

I have a 2017 stingray, base engine with a stick shift. I only have 3k miles on the car, but have noticed it has a off idle hesitation during any light throttle acceleration. It acts like the car is "Cold" and running lean, but it does it all the time even after warm up. In the "Eco mode" it is very rough as it switches from 4 to 8 and I'm wondering if this is normal. I've heard of people with other vehicles ( with automatic transmissions ) that they cannot tell when it switches between 4 and 8 cylinder. Mine is very noticeable. Is this normal?
Thanks,

Mike

BJ67

Off idle lazy throttle action is normal for a manual trans NA C7. Have never wanted to or experienced ECO mode though. Just never put the car in ECO mode.

Zjoe6

Normal. Do a search and you will see. Using a different throttle body can improve it. Luckily when I went to Spring Mountain owner school recently, I remembered to test the Grand Sport I was using there. It did the same exact thing. It's not a problem though. I had to push the accelerator really fast off idle to hear the sound. It sounds like it's sucking air for a short period of time and quickly goes away as it gains RPM.

redman76

A rough 8 - 4 cylinder transition is normal on M7 . . . takes some getting used to.

LuisZ51

Mine is very rough switching from 4 to 8 mode. I don't use it anymore. I took mine in for the hesitation and rough idle and they told me it needed a PCM update. After they supposedly performed such update I haven't experienced any issues since. Definitely no hesitation if you are in the right gear. If you're too high of a gear then maybe.

Kracka

A ported throttle body greatly helps. Frankly, the factory throttle body is a terrible design for a sports car and should have been kept to the Silverados it came from.

mxw1

mxw1

My hesitation is from a normal in traffic standing start, just as I engage the clutch and load the engine, as I add a little throttle there is a hesitation.

Do you remember if there was a TSB (Technical Service Bulletin) number associated with the PCM Upgrade?

Thanks,

Mike

Avanti

However, they don't all do it. My '18 base, M7 is just fine off idle, light throttle app. When I first read about this shortly after driving my car home from Kerbeck's I went out to see what I had missed for the entire 1600 mile trip home. Nada, zilch, zero.. I'm old enough, have/have had, and driven enough other hi-po cars from Lambos to a gaggle of B'ville race cars, to a Boss 429 to judge. It's not a universal phenomenon with manual C7s... as screwy as that may seem, especially if yours does it.

(btw, I've never driven mine in econ-mode)

LuisZ51

I don't think it's a tsb. I'll look at the paperwork tonight after work and see what they classified it as.

jim2092

https://www.corvetteforum.com/forums...o-know-it.html

ssmith512

Ya, what he said.......

My 2019 Z M7 is awful. I hate the off idle hesitation/lag/stumble, however you want to categorize it. First time I drove the car I stalled it 3 times! Havent stalled a manual in I dont know how long!! I felt like a dork. (Maybe I am dork, who knows....)

taz2016

I'm seeking clarification. Are those M7 drivers complaining of hesitation/lag driving in Eco mode? My 2017 suffers from no such affliction but then I never drive in Eco mode.

jim2092

They are not. If you never drive in Eco mode how do you know?

mxw1

My car has the off idle hesitation or stumble in all modes, not just eco mode.
I also stated that ;While in the eco mode is it very noticeable when it switches between 4 and 8 cylinder modes, it feels like the ignition is cycled off and on again for about 1/2 second.
Just in case these two problem were related...
Thanks,

Mike

Zjoe6

I love when a thread talks about two completely different things. Like listening to a crazy person talk. Don't make no sense.

Mike@SolerEngr

Mike, please check us out. This is what many of us perceive, but not normal by any means. Check this thread:

https://www.corvetteforum.com/forums...post1598646214

Thanks,

rrepp

Have you tried driving in sport mode? That is supposed to improve throttle response whether you have mag ride or not. Electronic throttle takes some getting used to as well. From what I know about Eco mode the benefits are not worth the aggravation. Some even say it's just not very good for the car. I never have driven my car, a 2019 stingray with stick shift, and mag ride, in Eco mode. I get really good mileage on road trips, provided I somehow manage to keep my foot out of it. Most people are shocked to hear I can get 28 miles per gallon on the highway. Throttle body will make a difference but will probably void the warranty, though I'm not certain about that. And if you hear that air sucking sound you're probably using more throttle than appropriate for your rpm's at the time.

Zjoe6

Really? Is there such a thing?

spinkick

Get the soler engineering throttle body. It's designed to fix the truck like off idle tip in hesitation.

I'm not affiliated but I do own one