I'm really not sure what to suggest. I used to have problems and I'd be very conscious of noticing if it ever happened again. However my 2005 4.8is has been absolutely perfect in terms of the transmission/engine logic. It never lunges or surges, it's the model of good behaviour. I drive around most of the time in Sport and it's smooth and responsive, the only time I take it out of Sport is if I'm approaching a junction from speed (just to ensure the gearbox doesn't change any lower than 2nd).

If you are using the latest software then perhaps the 2005 engine/gearbox DMEs work better with the latest software - it could be worth trying to get a replacement DME fitted.

Otherwise, have you had your dealer check for the VANOS Intermediate Valve Lever problem? This is a known PUMA fault item that causes very jerky engine behavoir including moments when the power can virtually cease to deliver.

The UK details are : PUMA 4736767 - dated March 3rd 2005 - Author, John Beckley, Master Technician.

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