New MAP sensor fitted, codes cleared and all is good in the world.
TCJ haven't really known MAP sensors to fail before but from memory I changed this before when I was fighting problems that turned out to be the fuel pump so it could be that only the cheapo sensors fail.
If it helps anyone else the symptoms were: really rich running, rough running, spluttering power loss / drop off. Started out very occasionally and a throttle blip would seemingly sort it, sometimes was at idle, sometimes not. Would occasionally drive ok but a little rough but the sort of thing easily ignored. When finally went it was rough as F, actually stalling when stopping but could just about be driven. Codes came up for O2 sensor shorted to voltage and no 5v to MAP sensor, I thought this meant wiring issues but changing the MAP sensor fixed it.
