Hi Barney, looks like you have got your work cut out here. I looked on ESi & the BARO uses the MAP sensor when the ignition is switched on & engine not running to find atmospheric pressure. There is a 5 volt link between EGR position sensor & MAP sensor.ESi also gave me the figures for MAP sensor engine idling & i think it was between 280mbar - 420mbar but my memory is fading at this time of night with a few chrismas cheers inside me, i will check tomorrow.I think your right by chasing why you have only 16" of vacuum, cam timing but having a belt change 18 months ago you like to think that is has been correctly, EGR being replaced so you would of thought that should not be stuck open , there could be air leak or exhaust blocked.I would like to know why the EGR was changed because of link between the EGR position sensor & map sensor, wiring fault may be, the 5 volt feed also goes into cam sensor.I know Rob that has been on a few course had a similur fault and it was the EGR connection plug full of water, may be cam sensor connection plug full of water.I have never experienced this fault in our garage but i hope this helps Darren