The product enhancement listed above #06162 - (12/13/2006) is a new software set that simply adds a broader range of operation to the Virtual Flex Fuel Sensor (VFFS) so that the engine will start and run smoother when various amounts of Ethanol is detected in the tank.
It has no effect on drivability when running gasoline containing less than 10% Ethanol. This update should only be performed on Tahoe’s with the last eight digits of the VIN below 7J275832

 

Finally, an answer to what the update was, thank you.

 

Why don't you go back to factory settings and try it again?

 

So ZX, I take it that this update has nothing to do with the V8- V4 mode.

 

Gas in IL has 10% Ethanol by default, I wonder if I'll get the new software?

 

That is correct; the Active Fuel Management software programming was not effected by this update.




And Tony, most states currently use blended fuel of 10% or less, what was discovered and what this update address's is the different qualities of base fuel stock / ethanol and also varying octane levels and mixture's. For instance; if you had ½ a tank of E85 but then refueled with 92 octane Premium unleaded the previous program may not make the necessary adjustments to the fuel control system and the engine could run very poorly.


Or something similar could happen if you filled up with E85 but the quality of the fuel was diminished from age as we are finding out is happening in some states that sell E85 for up to .50 cents per gallon more than regular unleaded, these stations seam to go through E85 at a painfully slow rate.

 

That makes sense. A little off topic, if I have access to e85, should I use it?

 

Only if it is less expensive otherwise; don’t even consider it.
The primary benefit is that it burns cleaner than straight gasoline and produces slightly more power (very slightly).
It won’t save the earth from the greenhouse effect or make your engine last longer.