Hello, Thanks for the replies, I haven't yet checked the fuel pressure & I wonder whether I wrote down the incorrect mass flow. The vehicle is coming back in on saturday, when I hopefully will get a bit more quiet time to fix it.I have now got another EGR valve, but today have mot tested a X12XE corsa which had no faults stored & passed the emissions fine, which I took some waveforms from.The egr position showed 1.6 volts & maf 1.48 at idle.The lambda earth was also the same at approx 280 mv, so either they both have floating earths or they are both faulty or my scope is measuring wrong.