Help with Alfa 155

Help with Alfa 155, what happens to me is that the mortor tends to be cut for seconds and works again it seems that the engine is stuck but one accelerates it and works again, before this problem I changed an injector peak of the same brown color but different numbering,. It worked excellent for a week every day, until I started with this problem, it does not work calmer that is to say an acceleration stays as if it is nervous in low, if one accelerates it suddenly it seems that it lacks air or something, it will be that someone has an idea of ​​what happens to it? Please a light for this alpha