sounds like air flow meter problems, if its a 1600 and the air flow meter part number starts 96FB or 96** then i would say that first or the throttle position switch?
if its an1800 then they are 93bb/fb items and are just simply mondeo mk1 (any, inc td) air flows.
way to tell on the 1600`s is if inlet is black plastic(air flow is same size at both ends) or ally (big air filter side,small engine side)

many years as a ford specialist, hope i can help.

Sean.