I've been having an intermittent fault with my A3 1.8T Quattro (2000) occasionally it would start on 3 cylinders when warm - now it only starts from cold and when warm will, without fail start on 3 cylinders. I have to leave it about an hour before I can start on 4 cylinders again. Snap-on Diagnostics code was; 17925 - Power supply relay for ECU (J271 or J363) Electrical malfunction P1517 intermittent Anybody know exactly what the fix for this fault is?? I would be grateful, it's driving me nuts. I also got the following fault but I'm not sure it's related :/ 17521 - o2 Sensor bank 1 sensor internal resistance too high P1113 intermittent.