skoda fabia 1.4 diesel - crank sensor problem - scoobysilver

ive got a 07 plate skoda fabia 1.4 diesel fault code was

16705 p0321 ignition distributor engine speed input circuit - g28 range performance

changed cam and cranksensor and also new timing belt fitted but still the same problem.car drives until you give a bit of stick and get to about 4000 rpm then the eml comes on

any help appreciated