Daniel Ricciardo has revealed a fuel-saving issue cost him up to "two seconds a lap" during a "painful" Qatar Grand Prix.
Ricciardo struggled for pace across the weekend at the Losail International Circuit, qualifying only 14th before going on to finish Sunday's race 12th.
"We had a very painful race," said Ricciardo. "Very early I had a fuel warning on the dash, actually on lap one already.
“I ignored it because it was strange to get that already and I was told to save fuel [but] I was saving so much to the point where the tyres got cold, the brakes got cold and we were just at times two seconds a lap slower.
“It was like we were not going to get to the end and I was doing so much saving that it was kind of pointless what we were doing because we were just taking ourselves further out of the race."
By the time he was instructed to stop saving fuel, Ricciardo conceded "the race was gone."
He added: "There was something that went wrong, a miscalculation or an error in the reading that forced us to do what we did.
“That is something that we have to look into because it dictated all the race.
“Ultimately, the easiest way to say it is we were a passenger for 75 per cent of the race.”