doing my head in

[bigcsxi]

i have a 2000 1.2 sxi 16v 1.2, having some ecu problems, when u first start the car it wont rev very high which results in it not going very fast, as it warms up it gets better then when its fully warmed up it wont rev over 3000 without the orange light coming on and it losing power big style, have replaced the o2, crank and the air mass sensor and its still doing it, any ideas? would appreciate your help.