I have a 2001 3.0 petrol/LPF X5
While driving the other week I got engine management light (ive read on numerous LPG threads on various forums that this is quite common as the engine thinks the fuel is too lean...)
Now onto the lights, these are the lights in question:

With these lights comes a loss in power. Turn car off and on again and it clears it.
Last MOT said "battery in poor condition" and ive just fitted a new head unit with a big bright screen (if that matters?)
Any ideas? Please dont tell me i bought a lemon! O_o