2019 GS Fluttering @ Low Speed
Thread Starter
1st Gear
Joined: Feb 2015
Posts: 1
Likes: 0
2019 GS Fluttering @ Low Speed
When travelling at low speed the car sometimes flutters. At fisrt I thought it was the car going from 4 cylinders to 8 cylinders. But after watching it that may not be the case.
Last edited by CVL; Jun 7, 2021 at 01:10 PM.
Burning Brakes
Joined: Jan 2020
Posts: 808
Likes: 399
From: NW Georgia
If it has a A8 automatic transmission and you are not running a Range Device, I would suggest getting one. What you are describing seems to be AFM going from V8 to V4 mode. Range Device will disable it and make the car run like it should.
Melting Slicks
Joined: Feb 2018
Posts: 2,172
Likes: 1,040
From: North Texas
I tuned the AFM out on my 17 using a Diablo I3. Not suppose to be detected by GM if the ECM is reset back to stock before they scan it for warranty work.
The Diablo sets the AFM 'switch' inside the ECM to off thus never allowing the V4 mode to engage. Kinda like running the car in manual mode.
The A8 in Europe and the M7 in the US has the AFM switch set to Off until you put the car in ECO mode. The correct way it should be done. Too bad the US got stuck with the always On setting in Drive mode. Thus the issue.
The issue in using a Range is that the unit is constantly resetting the DTC's which makes it extremely hard to trouble shoot a problem, get an inspection, etc. The Range works but is a bandaid type of fix, the correct way is to turn Off the AFM inside the ECM like the European A8 and the US M7.
The Diablo sets the AFM 'switch' inside the ECM to off thus never allowing the V4 mode to engage. Kinda like running the car in manual mode.
The A8 in Europe and the M7 in the US has the AFM switch set to Off until you put the car in ECO mode. The correct way it should be done. Too bad the US got stuck with the always On setting in Drive mode. Thus the issue.
The issue in using a Range is that the unit is constantly resetting the DTC's which makes it extremely hard to trouble shoot a problem, get an inspection, etc. The Range works but is a bandaid type of fix, the correct way is to turn Off the AFM inside the ECM like the European A8 and the US M7.
Last edited by Tinkertech; Jun 8, 2021 at 09:15 AM.
Le Mans Master
Joined: Mar 2010
Posts: 7,050
Likes: 945
From: DFW TX
Is the car an automatic? Could be the transmission "shutter". Good way to rule out the V4 to V8 stuff is just drive it in track and see if it stops.
Last edited by C7&7; Jun 8, 2021 at 09:58 AM.
