Been having a few problems with sensor faults on my Altea4 Freetrack. 2.0tdi 170(pd). Have replaced MAF, Boost Pressure Semsor and DFP pressure sensor. And fault still persists. Car starts with flashing coil light on, if I clear the fault it drives ok(no limp mode), but definitely down on performance and mpg. I have read on Ross tech pages about possible loom faults could be causing it. Has anyone else experienced this? Is the a particular part of the loom that I can focus on? Or is it just earthing issues, in which case which earth point to focus on? Any advise gladly received.