Does anyone have the new Silverado 1500with the ACTIVE FUEL MANAGEMENT where it drops it from 8 down to 4 cyl. I was wondering how it does on gas mileage. Any real world gas mileage would be helpful. Thanks
I have a NBS 07 Silverado 1500 Extended Cab 4WD with the 5.3L. The engine is aFlex Fuel model and hasAFM. I am not overly impressed with AFM to be honest. I sold a 2005 Silverado 1500 EC 5.3L(HO)4WD when I bought the 07. The 05 got far superior MPG without AFM. Everything about these trucks is the same, except for the body style obviously, but for the axle ratio and the AFM. Both EC's, both 5.3L's, both 4WD, both ran 265-17 AT's,etc... The 05 had a 3.42 gear ratio and the 07 has 3.73's.
The 05 got the following MPG...
100% City = 14-15
Mixed= 17-20( depended on how much was highway vs city )
100% highway = 21-23( highest was actually 22.7 )
The 07 gets the following MPG( so far hopefully it improves )...
100% city = 15-15.5
100% highway = 17-19( highest to date = 18.9 )
Decent MPG for a full sized 4WD no doubt but very disappointing when a newer truck, with fuel economy improvments, actually gets worse MPG then the truck you sold. GM has touted the MPG improvements in thenew GMT900 Silverado & Sierra big time but so far I am not seeing it.
As to AFM working. I do notice it when it changes mode but it is very smooth. More like going into an extra OD gear when going into V4 and like shifting down when coming abck into V8 mode. The longer you drive the less you notice it. I have not experienced the rough transition other folks have seen.
AFM on my truck does come on pretty easy when cruising along on a flat road with sustained RPM levels and speeds 45 MPH+. Does not stay in very long though. I don't believe in real world applications it is going to do much. In a controlled environment it might help but not much for actual people out on the road driving.