Sep.9 (GMM) Five races after the worrying events of Valencia, the looks of concern are back on the faces at Red Bull and Renault.
At Valencia, Sebastian Vettel's sure victory ground to a halt with an alternator problem.
Similar problems were arising at other Renault-powered teams, including Lotus and Williams, and so the French supplier reverted to an older alternator specification.
The problem seemed to have gone away, only for it to apparently return on Vettel's car in the Italian heat at Monza on Saturday morning.
"We don't know what has caused the problem," Renault Sport's Remi Taffin is quoted by Germany's Auto Motor und Sport.
"The only thing we could do is install a brand new part."