Transmission lag F31 335d

[DocSteve]

My 335d has what I think is excessive transmission lag after throttle input has been reduced or absent for a period. This seems to happen in any gear and any mode (i.e. it's not a throttle response issue and that's clear after experimenting with sport mode).

I guess the clearest way of explaining it, eliminating certain other confounding possibilities, would be to describe a scenario when I'm in sport or sport+ mode and manual control, I'm in a particular gear and the speed/rpm doesn't require it to automatically shift down: I come off the gas completely for a period of time then apply the gas again - there's a considerable lag before taking up drive (this is not throttle response or any turbo lag, this is take-up). This is somewhat unpredictable and it will sometimes take up straightaway. The only things I can find that may be consistent are a RPM of just under 3k and at least several seconds with no throttle input.

It's in for a service next week but it has a number of modifications (nothing to do with the drivetrain) and I don't want them to claim that something like suspension upgrades have voided any warranty,

Thoughts welcome!

Steve

[Mr Whippy]

Does it do the same in M(anual) sport transmission mode?

Ie, sport +, lever across to sport gearbox, and manual gear selection active?

[kingofdbrits]

Mine has long transmission lag but only when cold, happens everyday when I gently pull out of our village onto a NSL road, I've assumed its the car protecting itself? By the time I've got to the next junction I've got a bit of temperature the lag goes, i'm guessing, but perhaps yours still thinks its cold and continues with the lag?

[DocSteve]

Yes, I recognise the lag described when cold when pulling off but what I'm describing is quite different - happens when everything is fully up to temperature but at speed and also, in response to the above question, it does it when in (permanent) manual mode and gear. For example, I'm in 4th and expect it to pick up it won't where in other similar situations at different speeds/rpm or when throttle input has not been relaxed it will pick up very well for a turbo diesel with an albeit very advanced slush box.

[Charlie Croker mk2]

The "lag" you describe is entirely correct after gentle driving its just adapting to your driving ? Software updates frighten me , someone mentioned dealers will update the engine software to EU6 standard which dumbs down the engine and increases fuel consumption ?