Elderley neighbours car.A few days after filling up(half tank to full) at Asda car started poorly and wouldnt tickover.Dont think there is a link here? Vag com shows nowt out of the ordinary apart from 02 stuck at 1v at tickover which it just about manages at 600rpm.Sensor sooted up.Will start switching at high idle but only .3 to .6v ish.Vag com showsCTS at 20c all the time but voltmeter direct indicates correct voltage swing on warm up.Checked earths and all ok.Unfortunately cant check gas or pressures as loaned out gear...doh!Car runs well otherwise.Did find one corroded plugcap/plug and changed them.Have substituted o2 and cts with no change. What am I missing here guys? Thanks for looking, Tony