I've had two of these now and can say that what you're experiencing is NOT normal. Both of mine have a seamless transition between modes. Other than the DIC display, the only way I could tell was a very slight change in exhaust note.

 

Is the 6.2L engine in the Escalade direct injection instead of multiport? That can make a huge difference because the DI is so much more efficient. With the DI the compression of the engine can be greatly increased without the need for high octane gas or any of the like so it makes the whole engine way more efficient. GM seems to favor offering new technolgies like this in their high end vehicles for at least a couple of years before they let the 'common' vehicles have it. Emissions and fuel economy standards will eventually force this technology to all vehicles.

 

I have a 2010 Yukon. The car will get stuck (I guess) in the V-4 mode and depending on the force applied to the gas pedal will actually sit there and rumble and shake the car noticeably. It is especially bad between 30 and 40 but will occur at any speed. I have had the car back to the dealer and they say that GM will not warranty and that it is "normal". I can't believe that they expect you to pay $61,000 for a car that shudders and rumbles etc.

 

that's not normal, well, it is for a GM product, but it's still not normal. My 09 does not do that at all in 4 or 8 mode. take it back again, and file with the BBB that usually get's GM's attention.

 

al's yukon welcome to the forum..
I would be suspicious of the torque converter from other post I have seen about shudder and vibrations, as I have not seen a lot of issues regarding the AFM and I don't think the tech would say it staying in V4 mode for any amount of time when the accelerator is pressed is normal....
Take it to another dealer and have them ride with you and hook up the diagnostic tool to disable/enable the TC lock up and see if it still does it....

 

If it's stuck in the V4 mode, I'd expect it to shake and shudder as 4 cyl aren't up to lugging around almost 3 tons of road-hugging iron.

Normally just touching the accelerator will take it out of V4 mode.

 

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <wontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--><!--[if !mso]><object classid="clsid:38481807-CA0E-42D2-BF39-B33AF135CC4D" id=ieooui></object> <style> st1\:*{behavior:url(#ieooui) } </style> <![endif]--><!--[if gte mso 10]> <style> /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} </style> <![endif]--> al's yukon,

Do any warning lights come one when this occurs? Does it occur often or intermittently? I would also suggest taking the vehicle to another dealer.

Keep us posted.

Louis
GM Customer Service

 

After reading all of the posts which I find interesting I will include my 2 cents. My 07 Tahoe averages 20.8 using pure gas and 18.3 using 10% Ethonal crap....No problems at all with the AFM and a slight vibration due to a tire issue. I rarely see mine in 4 mode unless I am coasting and I am thinking about getting a cable to hook up my EFI LIve and check the specs on this and see if I can muster some changes to the ECM. I used this tool for many years on my 04 Duramax which has 376k miles and it does a very nice job of changing values to suit your needs. It works in the same fashion as Hypertech or Superchips and Edge. The user can control all of the points they want to or as little as they want to.

 

Thanks for the info. Louis, no lights come on and i have been to two dealers. Problem is since GM published document 06-06-05-001E the dealers won't touch it because they won't get reimbursed for any work. From other people that I know who have similar vehicles and from the posts here mine is not just a slight vibration for a shorrt time. I can't complain about the gas mileage as I have obtained 21 on hwy with 2 or 3 passengers and a 100 lb. german shepard in the back. It is intermittant and does relate to the V4 to V8 change.

 

20.8 that's nice! the EPA comes up with the magic (random) MPG figures for new cars using pure gas... There's ONE pure gas dealer near us, and by near I mean 1/2 hr drive.

Ethanol ruins boat gas tanks, destroys engines, and causes more pollution than pure gas.

But, hey, if I made $700,000 / year and had to pander to voter's... I'd have done the same thing, right?