S3 indicators sound very complicated.
Fulvia 3 indicators same as S2..... I think the self cancelling mechanism was not set up correctly, and part of the throttle problem could be due to the Pedal rollers which over 50 years get sticky (affects all Fulvias) and improved by fitting mall ball bearing in place.
Who is this guy? To take a random car out for a run is not representative. Fulvias are the most delightful cars to drive if properly maintained.