Strange one this, Went to a customers about 6 ish last night - was there for around 2 hours. when i left i started the engine and it imediatly stalled. started it again and it was fine. stuck the xenons on and set off. as driving along the needle was jumping up and back down to correct reading as if someone was zapping it. i could make it go away by turning both my main lights and side lights off. after driving for 10 mins it seemed to stop anyone have any ideas?