2003 Yukon have that cyc shut down mode?

[1yesfan]

Does my 03 Yukon with 5.3 have that cyc shut down mode for improved MPG?

 

[01ssreda4]

No.......

 

[1yesfan]

Good I hear it is not real good thing on these motors. True?

 

[iamdub]

It'*****-or-miss if it kills your engine or not. I don't consider the AFM model to be a 300K-mile engine like what's in your '03. As far as AFM being effective, I believe that largely has to do with the areas in which people drive. Where I drive, which is 50/50 highway/city, it's more of a hindrance. There are very few occasions during my drives where I can maintain a steady speed long enough to stay in 4-cyl mode. It's constantly switching back and forth. I'd rather sacrifice the 1-2 MPG that I MAY be gaining to save my engine in the long run. People that drive for longer distances around 60 MPH or less with no inclines are about the only ones to really benefit from it.