The problem is believed to involve damaged piston rods, with Cosworth's Alex Hitzinger saying last Friday that the independent engine maker had 'neither the money or the personnel' to put together a quick fix.
Nico Rosberg and Mark Webber were eleventh and fourteenth in Saturday's single morning session, which ended with two hours to go until the 'knockout' session.
In chillier morning weather than on Friday, the Ferraris – led by Michael Schumacher – set the pace, with Renault's Fernando Alonso down in sixth place.
Kimi Raikkonen, tenth before qualifying, continued to struggle with the handling of his McLaren with one or two spins. Also in a spin was Giancarlo Fisichella, in fifth place.