the change from e9sf to f1sf denotes a circuit revision or update, now whether that update actually involves a change of required internal voltage i don't know. knowing ford there probably was no circuit change at all- just a maf body revision i think.
if that is the case then something else may be triggering that code- continuity problem in the wire? i find that code very strange if the measured voltage of the '89 maf was exactly the same for the original one.
does the check engine light stay on or does it flash at some point when opening the throttle?
if that is the case then something else may be triggering that code- continuity problem in the wire? i find that code very strange if the measured voltage of the '89 maf was exactly the same for the original one.
does the check engine light stay on or does it flash at some point when opening the throttle?