I had similar problems with my 147 JTD m-jet. I've been down the same road ... MAF, EGR valve, just when I thought it was fixed more errors ... also had the turbo boost sensor and accelerator body changed and turbo overhauled before it was diagnosed as a turbo pressure spike, something in the control system wasn't reigning the pressure in and the boost sensor would hit its maximum 5V readout and the car would trip out into safe mode. I can't say if you're having the same fault as me but it's the same car, similar sounding troubles, I went round and round for 8 months chasing errors until it finally got sorted and hope I can save you some time on yours!

The remap was pretty much the only thing that could sort it, the garage hasn't got the software or the know-how to start monkeying about with engine settings but remappers know thios sort of stuff inside out. The turbo has been brought in more gently giving the control system/ actuators a chance to keep up, plus I've got more ultimate power at the top end, better fuel economy, more torque and a gentler increase in torque and power than I used to have. Far more driveable. Most of the decent remapping companies out there will give you a 14 day money-back guarantee, give them a bell and see what they can do.

It might be worth getting it on the diagnostics to see what the live data's doing, especially if any error codes come back vague and don't point to any specific sensor. I can't say your issues with your car are the same as mine and the remap will sort it but it certainly helped me.

You don't NEED a remap but it sure is fun, especially with the 16v m-jet diesel!