Listen to this article Ahead of his home grand prix weekend at the Circuit de Barcelona-Catalunya, Sainz finished second in opening practice on Friday before taking fourth in FP2, ending the day three tenths of a second off teammate Charles Leclerc’s benchmark time. But Ferrari has now revealed that a fuel system issue on Sainz’s car has prompted it to complete a chassis change ahead of Saturday’s running in Spain. The switch was reported by FIA technical delegate Jo Bauer in his most recent update on Saturday morning, confirming the scrutineering declaration form for the car had been completed after the chassis change. Ferrari subsequently confirmed that this was “due to a fuel system issue”. There is no penalty or sanction for the chassis change. Ferrari debuted a number of updates for its F1-75 car on Friday at the Circuit de Barcelona-Catalunya, which Sainz felt had “definitely got potential” as the team looked to get back in contention against Red Bull at the front of the pack. “We’ve seen some changes in the behaviour of the car which is good when you bri …