random engine stopped

[Mk2_pete]

right guys cars been driving brilliantly recently having changed the injectors until today when it just randomly stopped i thought i had stalled it pulling out of a junction. I tryed to restart it it cranked over for ages and then ran as rough as hell then a couple of seconds after the oil pressure warning light came on stopped the engine and towed it home stripped out the injectors thinking the might be the cause of the problem. once back together i realised the battery was flat so its currently on charge whilst i was sat in the car the steering motor kept powering up and the rev gauge kept flicking up and down anyone have any ideas?