Bx Running Problems

[bazil_205gti 22]

hi there i have just put a bx engine in my 205 have used all the bx parts including loom for some reason when on throttle the engine hunts up and down, could this be due to a fualty throttle position swith? also are the mi16 throttle body and airflow meter and amp all the same parts as the bx?

 

any help would be great really want to get this thing on the road

 

Matt