Bit of an update. I realised there were 2 hose clips half way down my egr to intercooler pipe. Assumed it was a 2 peice pipe. Alas no. Its split and had a bodge of a repair. Basically a tube has been shoved in and clamped up. But there are splits starting from the clamps. Without a doubt I will be replacing the pipe. But is it a possible cause??