Lewis Hamilton was fasted again in second practice for the US Grand Prix but Nico Rosberg was in close pursuit.
Sebastian Vettel will start from the pit lane for Sunday's United States Grand Prix as penalty for a power-unit change.
Lewis Hamilton led a truncated Formula One field at the end of the first practice session ahead of the US Grand Prix.
Caterham are just two weeks away from being wound up unless a buyer can be found for the ailing Formula One team.
Fernando Alonso has again left his fans playing a guessing game over his future.
FIA president Jean Todt is to review the shock financial downfall of Marussia and Caterham over the past week.
Sauber team principal Monisha Kaltenborn believes drastic changes need to be made after the demise of two F1 teams.
Sebastian Vettel has indicated hopes of being released early from his Red Bull contract were blocked by the team.
Marussia driver Jules Bianchi remains "critical but stable" in hospital following his Japanese Grand Prix crash.
Daniel Ricciardo believes the demise of Caterham and Marussia would represent a bitter loss for Formula One.