knock sensor trouble

[djbrowney]

hey you, back with more problems lol, 2.0 16v in my nova, when hitting 3500 or there abouts engine managment light comes on and the engine goes into limp mode, half power goes like a bag of poo. but it only does it sometimes, fault code said it was knock sensor.
so went to vauxhall brought a brand new sensor but it still coming on when it want to whats causing this please HELP !!!

[Jon_nova1]

your engines knocking?

[djbrowney]

no mate, not at all, engine normally runs like a dream other when this sensor plays up lol

[Adam]

Is knock sensor the only fault that came up?

[burgo]

i tak it you have erased the fault?

[djbrowney]

yer, other than the ones that come up because the engine aint running can remeber what they are

[djbrowney]

have erased it many times