Sluggish accelerating at 30-50mph

[91RS]

If it doesn’t do it in tow mode then a good tune will fix your issue and make the truck much more drivable.

 

[cycho]

MY 2013 XLT does the same thing. I chalk up to being under powered.

 

[wjburken]

MY 2013 XLT does the same thing. I chalk up to being under powered.

This is what we had going on with our ‘09 Suburban LTZ. My wife hated it, thus our return to the 6.2L XL Denali family.

 

[YukonXLMan]

I'm no expert, but I'd take your test results as success in that they show nothing major is wrong with the vehicle - all works well in trailer mode. I had a similar perception with my 2017 when I got it used with only 48K miles. Mine would feel good in first gear, but will only stay in second gear from 1500 to 1700 rpm then immediately drop into 3rd; and if I wasn't ******* the gas, would drop into 4 cyl mode as well. Felt like I was driving a VW bug. I chose to test a Range AFM delete and it helped a great deal in that the auto stayed in 8 cylinder mode and was now far more responsive. Now when I want immediate response in town, I shift to tow mode with the Range plugged in and play. The tow mode makes full use of 2nd gear on my Yukon XL and coupled with never dropping out of 8 cyl mode, provides instant ponies for use. Strangely enough, since using the Range, I also increased my MPG by 1.1 mpg in town. Cannot explain it as the result is counter-intuitive to me, but it's consistently that or a bit higher on the highway. Will do the full AFM Tune delete once warranty expires.

 

[Richard Blakely]

If it doesn’t do it in tow mode then a good tune will fix your issue and make the truck much more drivable.

What would you say if I told you that my tahoe runs 200% better if transmission is in the trailer mode? It climbs hills with no hesitation and shifts much smoother

 

[swathdiver]

my 2012 Tahoe with 6 speed transmission is very sluggish when accelerating around corner especially. Changed max air flow sensor but no help. Runs fine cruising. Should I suspect fuel injectors or spark plugs next?

BlackBear tune. To my surprise and delight, tuning the transmission made the truck drive very different and is much more responsive and I had him down it down some as those downshifts to 1st coming out of a u-turn tend to startle my wife and I. As we complete the turn and straighten out, the truck is doing about twenty and already in 3rd and as you lay into it, the transmission drops down to 1st gear and the motor takes off for 6,000 rpms like a rocket, the whole front end of the truck lifts up and my foot has yet to push the gas pedal to the floor boards! Wheweee!

There are two bridges on a regular commute that cause the transmission to drop from 6th to 5th or 4th. All the rest she stays in 6th and doesn't even unlock the converter. The only exception being while burning low octane gasoline, never does it on 93 or E85.