Help please :( poorly corsa, knock sensor..

[Ashley92]

Hello, i have a corsa sport 1.4, has piper cams fitted, was running fine did knock abit on certain revs, ecu went down struggleing to start now got new ECU, chip and transponder, car starts and drives BUT engine management lights now on, its revs to 5000 rpm and bounces, i plugged it up to a scanner its came up knock sensor, now heres the question.. Is this a coincidence that ive changed ecu now this has gone down and should order a new sensor or is it because of the ecu? my friend changed ecu on his car and it ran fine after :S

If anyone could help would be great!

Thank you Ash