Engine wont drop below 1500 revs when lifting off throtle

I.A.C.V ? (idle air control valve )

its just had a sechand engine put in could it be auto box prob

Very unlikely to be auto. box , but anythings possible . I.A.C.V sticks and holds throttle open .Can whoever fitted engine not get idle speed down ? 1500 rpm is dodgy with an auto box .

thay have tride every think. say now that i should take it rover for a dinno test and ive got to pay for this

sorry not dinno but adiagnosis test

This is what happens when you put s/hand parts on cars .If you put car into Rover dealership for a diagnostic scan ,it could cost you a fortune. They may not even want to get involved with car after they find out another "garage" have fitted s/hand parts .You don't need to go to dealers for scan , any decent garage /tuning specialist should have equipment to check out .Usually plenty of local tune up centres in Yellow pages.

have all the vaccum pipes and hoses been checked? sounds like an air related problem to me!!