Just bought a 182, turned key and worked first time then turned off and back on wouldnt work, bump start works, friving it home and the headlights start to flicker then my speedo stops working, 2 mins later all lights are out and I have lost power, foot to the floor and only revs tiny bit, won't start, will bump but die, I don't think it's battery or alternator, the way it's acting it's some sort of electrical fault, any ideas much appreated!