[JT58]

Is it normal for the RPM’s to fluctuate on the highway in 8th gear going a steady speed, flat surface- say 50, 60 or 70 MPH? I notice on mine that the tach, the RPM’s will raise and lower by 100 or so RPM when I am at a perfectly steady speed holding the gas pedal steady. The tach will go up and down every say 10 seconds- up 100 RPM, then down 100 RPM. I am guessing that it is 100 RPM, it could be 150 or 200- I see the needle move and can feel the engine RPM's raise and lower.

[Spartan268]

When it fluctuates do you see it switching between V6 and V4 mode?

[JT58]

HMMM is there a way to tell when it's in 4 cylinder mode?

[SuperSound]

Originally Posted by JT58

HMMM is there a way to tell when it's in 4 cylinder mode?

Use the MPG displays. Depending on whether you have the basic DIC or the 8", one of the fuel economy displays will show it.


Do you feel a shudder/vibration?

[JT58]

No shudder or vibration at all, car shifts normal. Just the RPM's fluctuate when in 8th gear while maintaining a steady speed. If I let off the gas and coast, the RPM's do not fluctuate. It also downshifts properly too when slowing down. I have never had another automatic vehicle do this. I'm curious if any one else with a V6 A8 does this and if it is a "normal" characteristic of the car.

[SuperSound]

Originally Posted by JT58

No shudder or vibration at all, car shifts normal. Just the RPM's fluctuate when in 8th gear while maintaining a steady speed. If I let off the gas and coast, the RPM's do not fluctuate. It also downshifts properly too when slowing down. I have never had another automatic vehicle do this. I'm curious if any one else with a V6 A8 does this and if it is a "normal" characteristic of the car.

Try replicating it, except use cruise control this time. If it doesn't do it with cruise, then likely you varying the pedal without realizing it. If it does it in cruise, then obviously something is up.

[i007spectre]

My V8 does this but only when I am going between 60 and 70 mph. The tach bounces all over the place and the car keeps trying to go into V4 but immediately goes back to V8.

[BrianWilcox]

On my 2017 SS, I had a shudder and RPM shift up 100-200 during highway steady cruise.

Dealer replaced ALL tranny fluid (power flush) with a new viscosity fluid per GM bulletin.
It worked.

[JT58]

It may be that the load is so light that it is going from 4 to 6 cylinders and vice versa. I will try cruise and see how steady the RPM is. Hopefully the tranny is not slipping to cause the variation.

[Need4Camaro]

I want to note that in the V6, 50 MPH is RIGHT ON the crest of where the car would like to downshift into 7th gear, what you could be experiencing is the torque converter unlocking and preparing to shift but the unlock gives it JUST ENOUGH power to keep it in 8th.. Seriously, these cars do NOT like to use 8th gear below 53 MPH.

It holds 7th from about 42 MPH all the way to 55 MPH driving normally then shifts to 8th..downshifting it will "tolerate" as low as 49 MPH but it REALLY hates it and its hard as heck holding it there even in manual mode... My opinion is, you're literally not going fast enough. I've had the thing up to 90 MPH and only turning 2 grand RPMS...unbelievable how overgeared these cars are.

[Spartan268]

Originally Posted by Need4Camaro

It holds 7th from about 42 MPH all the way to 55 MPH driving normally then shifts to 8th..downshifting it will "tolerate" as low as 49 MPH but it REALLY hates it and its hard as heck holding it there even in manual mode... My opinion is, you're literally not going fast enough. I've had the thing up to 90 MPH and only turning 2 grand RPMS...unbelievable how overgeared these cars are.

I ****ing love it Globs of power to boot when you kick it down a few gears. These cars are mean't to be driven fast and I have no complains with that.

Coming from a G35 with a short 5 gear auto. It use to go at 90mph in the area of 3-4k RPM. It has a redline of 6500RPM. Hated going on the highway with it despite it being a GT kind of car on paper apparently.

[Rock-It Man]

How many miles on the car?

My 2010 A6 did this on the highway, too, but only early on. Don't know whether it's a break-in thing or a controller learn thing, but it went away.

[Need4Camaro]

Originally Posted by Spartan268

I ****ing love it Globs of power to boot when you kick it down a few gears. These cars are mean't to be driven fast and I have no complains with that.

Coming from a G35 with a short 5 gear auto. It use to go at 90mph in the area of 3-4k RPM. It has a redline of 6500RPM. Hated going on the highway with it despite it being a GT kind of car on paper apparently.

I also have a 2 Door G37 Coupe and although the displacement is nearly identical the way they drive is night and day. The G37 seems like it has more low end grunt and harder pull from a dig but on the highway the Camaro wins hands down it just has so much of its powerband that isnt even tapped until you reach nearly tripple digit speeds. The G37 is pulling 3.5K RPMS at 80 MPH and the Camaro is BARELY sitting at 2 Grand... an another thing is you can be moving at nearly 100 MPH in the Camaro and it only feels like you're doing 75.

People who keep dogging these V6's obviously haven't driven one, while they're not a power gobbing SS, they're definitely no slouch either.

[laynlo15]

My SS A8 does the same thing. Doesn't even bother me anymore.