Don't know if I can suggest a cure, by my 4.4 behaves somewhat like your 4.8. When I'm driving around the neighborhood and slow down to turn a corner on a residential street - I'd say down to about 15mph, my 4.4 takes the corner in 4th gear and is bogging coming out of the turn. Then when I get on the gas again, it takes a bit of a push on the gas to get it to downshift and when it does, it certainly doesn't behave like the luxury SAV it's supposed to be. Driving around in manual mode cures it 100% but I wish auto mode was a hell of a lot smarter. It should be taking these slow corners in 3rd gear IMO, not 4th or perhaps even 5th sometimes. And you (I) can forget about sport mode around the neighborhood - 5500 rpms around the hood probably doesn't sit well with the neighbors...

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'08 335i Coupe - Barbera Red / Saddle Leather / Light Poplar Wood / 6spd Manual
Options: Sport, Premium, Cold Weather, Comfort Access, Active Steering (awesome!), Power Rear Shade, IPod Adapter, Navigation w/IDrive
Mods: M6 Wheels, Split Armrest, M-Steering Wheel, Euro Light Switch w/Rear Fog Lights, Short Shift Knob w/Matching E-Brake Handle, Clear Reflectors, CDV, Clear Bra

Retired:'04 X5 4.4i