Red Bull owner Dietrich Mateschitz says engine supplier Renault's poor performance has "destroyed" the team's enjoyment of Formula 1.
The partners have clashed several times this season, with Red Bull publicly voicing its disapproval with the French manufacturer as the engine has been unreliable and underpowered and Renault arguing that Red Bull's behaviour is damaging.
A series of engine failures have left both Daniel Ricciardo and Daniil Kvyat on the fourth and final engines of their allocation, making penalties inevitable.
The four-time world champion team is fourth in the constructors' championship, 231 points behind leader Mercedes after seven races with a best finish of fourth.
"Beside taking our time and money they have destroyed our enjoyment and motivation - because no driver and no chassis in this world can compensate for this horsepower deficit," Mateschitz told Speedweek.
"In addition, our chances were so scuppered by aerodynamic regulations which meant that chief designer Adrian Newey could not weave his magic on front wings.
"Now we have used our fourth engine, which means we are penalised on the grid.
"How many more things have to happen before we lose all enjoyment?"
Mateschitz added "there is no alternative to Renault" in 2016 should Red Bull want to end its contract with the French manufacturer one year early.
The Red Bull boss also hinted that the team may leave before its contract to compete in F1, which runs until 2020, expires.
"Sure, there are contracts for Formula 1 participation," he said.
"How many teams have dropped out of Formula 1, despite already contracts? You cannot hold someone if he wants to get out."
Should Renault leave the sport at the end of its contract - or indeed earlier - Red Bull would have to become a customer unless it could entice a new manufacturer into F1.
On the prospect of using a customer engine, Mateschitz said: "You get an engine which is good enough to score points but it will never be good enough to beat the works team.
"With a customer engine, you have no world championship chance, you will never become world champion.
"If we realise it, we have no chance of a world title because you have also lost an aerodynamic advantage.
"Then we lose all pleasure and we are bit-part players."