2002 a4 2.5 tdi. ok it all started with the esp triangle coming on every now and again and the brake light sticking on sometimes, then the glow plug warning light came on, this was happening once a week, fitted a xenon light kit and the abs light came on within hours of fitting said kit, after 2 weeks of abs light mostly coming on when i turned the lights on i removed the light kit and all fault codes removed, after a week air bag light came on a few times then stayed on and now a fault with the needle lift nozzle cannot be removed, engine now runs with a slight surge pulsating at a constant speed, all these things can,t go wrong at the same time when i had the xenon lights fitted i did notice the beam very slightly pulsing...could it all be down to irregular voltage blowing sensors?? i just dont want to fix all the faults without finding the root of problem...sorry if i've used up the entire supply of the forums ink.... any help would be more than welcome...i got a 1997 a6 2.8 quattro aswell but thats another story!!!