erratic idle

[ben 3695]

have a 09 2.0 tsi,bought it from auction been having problems, been in dealers. The story is it got water though windscreen needed new body control and can gate way, inlet manifold cause flaps arm was worn, replaced timing chain due to stretch, done compression test new plugs and coil packs,new speed sensor, but still got erritic idle doing my head in any suggestions, vag com bringing up code p2015, also when you disconnect the speed sensor on the inlet cam it idles fine but goes into limp mode help is needed