PETROL ENGINE EGR VALVE

As per topic title, car is a 2003MY Polo 9N 1.4 16V 75PS, due to regular pinking and now intermittant EGR low flow fault getting logged, I checked the stored settings of the EGR, removed it, the TB and the interface plate. I'd recon'd that cleaning the EGR and the TB were purely cosmetic as either any build up is impossible to reach (on the EGR) valve or of no consequence (on the TB) - although the interface plate really was dirty around the EGR valve gases inlet area. I've put it all together, adapted the EGR and the TB, but, the original "min" voltage position was 0.77V after being off the car and back on, the "min" voltage position is 0.95V then after another adaption when the engine was a bit hotter, "min" voltage position was 0.92V. So, is this EGR valve now not closing fully, and if so how can I clean it other than spraying with carb cleaner which flashes off too quickly to let it soften or rinse off any carbon build up? New valve time??

Edit, BTW the "max" voltage position seems to have stayed "okay" - ie same as original stored value.

Edited 23 July, 201213 yr by rum4mo