Red Bull has been forced to push back its deadline to announce its 2016 plans as discussions to secure an engine supplier remain ongoing.
The Milton Keynes outfit has threatened to pull out of the sport after failing to secure a engine deal with Mercedes and Ferrari, leaving the team without a power unit supplier for next year.
After severing ties with existing supplier Renault, Red Bull had hoped to make a decision before the end of October, but has been unable to conclude talks with manufacturers.
It was revealed over the weekend that the team has investigated the possibility of switching to Honda engines for 2016.
With options fast running out, there is also hope the squad may be able to repair its relationship with Renault to remain with the French manufacturer.
Team boss Christian Horner says the process of securing engines is ongoing but remains confident Red Bull will be on the grid next year.
Although, he admits a decision is required imminently to prevent further delays in designing and building its 2016 car.
“We are working very hard to try and find a solution and hopefully we will be able to do that,” Horner told Sky Sports F1.
“There are a few blockades but somehow we will find a way.
“We are absolutely massively tight on time and ideally we would have had that decision prior to the end of October but that isn’t the case. Hopefully we will be homing in on something soon.”
Red Bull enjoyed one of its strongest showings of the season at this weekend’s Mexican Grand Prix, with drivers Daniil Kvyat and Daniel Ricciardo finishing fourth a fifth respectively.