BMW Questions? Ask a BMW Repair Expert for Answers.
I'm assuming that there's no engine fault / check engine light on so in which case I'd say that this sounds like a lack of fuel and could be a lack of fuel pressure from the electrical pump at the tank.
If the connections to the pump are corroded or damaged then the pump could stop at any time or could not be running at full speed. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse,
Ideally measure the pressure at the injectors and if this is low check the pump as described and also consider changing the fuel filter as if this partially blocked this too will reduce pressure.
thanks for the extra information
P1030 BMW - Valvetronics Monitoring Sluggish Movement, so this would result in the inlet valves not being lifted off their seat and so choking the engine as with the valve tronic system the regular throttle is only usd to regulate inlet manifold vacuum
This can be cause by a wiring fault to the Valvetronic Motor or perhaps a failed motor itself.
The first step would be to remove the beauty cover on the top of the engine and inspect the wiring
If you don't find a wiring fault and want to replace the motor, here's a walkthrough to get you through it:
Ok in that case check the connection to the motor and both cam sensors and it would also be worth checking that the high power wiring to the motor in is good condition with no corroded connections and stiff sections of wire , if you find any of these then replace the wiring
do you still need help?
Bear in mind that the site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert. so if my answers have been helpful please rate my answer.