09-2011 Tahoe Questions

[jbangelfish]

Hi all

 

Am trying to sort out all that is new in the Tahoe. I have a 99 Tahoe LT, that I've loved and hated, (too many repairs but love to drive) looking to replace with a newer if not new one.

 

I have many concerns, number one is cylinder deactivation, the very phrase is scary to me. Yes, I'm going back to the old Caddies that failed miserably. I know technology has come a long way. I've read both favorable and unfavorable reviews. One cited the vehicle just dieing on the highway, others say the mileage improvement isn't that great. Most just say they hardly notice.

Since my 99 with 5.7 consistently would get over 20 MPG on the highway, I have trouble understanding the big advantage to cylinder deactivation on the new 5.3 with 3.42 or 3.08 rearend, vs the 3.73 on the old ones. Is it on all newer Tahoes and do I need to be afraid of it? I also see that they do not rate the two rearends differently in mileage, citing 21 MPG for all Tahoes except the hybrid, which is only a tad higher.

 

Mileage is far from being my only concern. If these things will run better than 20 MPG on the highway, I can live with that. It's a starting point for discussion as I said cylinder deactivation just sounds scary to me.

 

Thanks for any input,

 

Bill

[MRMDFY]

AFM is a stupid feature created for all the wrong reasons. My Silverado has it and while I don't have any problems, per se, it certainly isn't a benefit. Get a EFI-Live tune from Blackbear or the like and you can have the feature disabled if you like. You'll want the tune anyway.

[Pumper]

Really I don't think that there is anything to be afraid of with AFM. The downside is that I am pretty sure that it produces no gain in mileage. I don't think that you can go wrong with a new Tahoe, but you probably won't be getting 20 MPG on the highway. The new ones are bigger and heavier than the Tahoes that they replaced.

 

They really are great trucks and I don't think that you will be disappointed.

[RyanbabZ71]

My 08 2wd has only seen 20 mpg 2 times running 60-65. Highway is more like around 18 (this running 70 mph).

 

22K miles here and has been a great SUV (knock on wood). AFM has been flawless and I cant even tell its there.

[MRMDFY]

My 08 2wd has only seen 20 mpg 2 times running 60-65. Highway is more like around 18 (this running 70 mph).

 

22K miles here and has been a great SUV (knock on wood). AFM has been flawless and I cant even tell its there.

 

This continues to befuddle me. I average 10.4mpg. Best freeway trip (granted there's mountains to cross) was 15mpg. 20k miles, 4x4, VMax, 3.73 gears, 295/65/18 tires, Prem. gas. I probably average 70-75 on the freeway.

 

:shrug:

[jbangelfish]

AFM is a stupid feature created for all the wrong reasons. My Silverado has it and while I don't have any problems, per se, it certainly isn't a benefit. Get a EFI-Live tune from Blackbear or the like and you can have the feature disabled if you like. You'll want the tune anyway.

OK, I figured you could disable it without losing much if anything. I've pretty much heard that it only goes to V4 mode downhill anyway. If you have the computer readout for mileage, you can watch a pretty heavy SUV getting 40 or 50 MPG, momentarily without killing 4 cylinders. This is all handled by the computer I suppose, fuel metering etc. You don't need the nuts to go down hill and gas consumption drops off considerably, the equivalent of taking your foot off the gas and coasting. The computers now do this for us. I really do not see the advantage but it seems to be in them all. I just spoke with a car dealer about my concerns and he said it gains a mile or two per gallon. To be honest, I have serious doubts about that due to the above mentioned factoid. They can all do pretty well downhill or with a strong tail wind. So what.

 

Next question is this: If we tamper with this stuff and disaable the deactivation, do we void the warranty. That would be bad. Thanks,

 

Bill