Daniel Ricciardo has conceded he was left scratching his head after falling down the order at last weekend's Spanish Grand Prix.
Ricciardo has struggled since moving from Renault to McLaren ahead of the 2021 season.
In Barcelona, the Australian outqualified team-mate Lando Norris for the first time this year but on Sunday was powerless to prevent a slide down the order from ninth to 12th.
Although unwell and suffering from tonsillitis, Norris climbed from 11th to eighth.
Asked if there had been any divergence in the set up of the two cars, Ricciardo conceded: "I mean there are always little bits here and there but to be honest, I hope to find something else like 'oh wow, this was wrong' or something.
"Because when it is set up or stuff, you can say there is a couple of tenths but I know I was just slow really so I am sure at times I was probably a second, if not more, slower."
Ricciardo problems "more than set up"
Although Ricciardo scored McLaren's first win since 2012 at last season's Italian Grand Prix, his results have otherwise been a mixed bag.
This term has been particularly tough for the 32-year-old, with just one top 10 finish scored from the first six races.
BY way of contrast, Norris has registered points on four occasions and stood on the podium at Imola.
"This felt more than set up so hopefully there is something because I certainly tried to - obviously I am experienced enough now to try different things throughout the race and try to push on the tyre, try to be conservative and try to approach the corner in different ways," explained Ricciardo.
"The net lap-time by the end was the same whether I used the tyres or not. One of those where you are scratching your head."