Red Bull was on Friday evening due to decide about using KERS for the rest of the Malaysian grand prix weekend.
After heading both practice sessions at Sepang, with his teammate Sebastian Vettel having dominated in Australia two weeks ago, Mark Webber said the team had tested with both cars running the energy-recovery technology on the opening day at Sepang.
"Whether we run it on Sunday or not, we will decide in the next 24 hours," said the Australian after practice.
Team boss Christian Horner indicated the decision would have been made late on Friday.
"The system has run well and obviously reliably, so a decision will be made on it no doubt later this evening," he said earlier.