Have you read the thread thoroughly? Check the brake servo vacuum pipe. Is it loose at the inlet manifold end?

 

It often splits at that end and when you brake/accelerate the engine rocks back/forward and the pipe pulls back opening up the split. That in turn allows air in and the idle mixture is weakened and revs all over the place, also leads to loss of brake servo assistance - brake pedal goes hard and a lot more effort required to brake, dangerously so.

Thanks xman. I did check the vacuum pipe and it's fine . Also when i want to stop the erratic tickover i can touch the accelerator pedal to bring the revs just past 1000 and it comes back to 950 revs ans settles down . i think Skoda have a problem with the ECU to be honest. But thanks for the advice . 

@adriantomlinson - I can believe that; my Octavia occasionally starts and decides to idle at ~1_200rpm. A throttle blip usually gets that back to normal though.

Dicky throttle position sensors are common on the htp engines.