Mercedes trackside engineering director Andrew Shovlin says the Brackley squad failed to improve its car during its two weeks in Austria and believes that something the team is doing "isn't right".
Last weekend, Mercedes conceded its fifth consecutive defeat to rival Red Bull Racing who now leads the Constructors' championship by a 44-point margin.
Lewis Hamilton and Valtteri Bottas qualified fourth and fifth respectively for the Austrian Grand Prix, and while the Finn finished runner-up to dominant winner Max Verstappen, early damage sustained by Hamilton relegated the seven-time world champion to fourth.
Shovlin said Mercedes was left with more questions than answers after its second round of racing in Spielberg.
"We haven't been particularly strong here in general," Shovlin said after last Sunday's race.
"That isn't so much evidenced in the gap to where Red Bull are, but just how much pressure we were under really with McLaren and Lando, who did a great job, but ended up ahead of us.
"Austria wasn't suiting the car and we've not made any real inroads into that over the two races here. That's a bit of a longer-term thing to look at.
"Then also the very soft compound, the C5, just wasn't giving us as much in hot conditions on Saturday as we were getting from it on Friday and there's another question there.
"It wasn't as much that we did anything, obviously wrong. But when you look at where the performance was, we would have to acknowledge that there is something we are doing that isn't right."
Shovlin believes that a better performance in qualifying wouldn't have changed Mercedes' fortunes on race day.
"We were the makers of our own issues a bit with the poor quantifying, so that made it very, very difficult to be even thinking about challenging Max," added the Briton.
"Even if Lewis had started one behind him, I don't think it would have would have troubled them.
"So overall, bit frustrating really both from a performance point of view and the fact that we need to keep the car in one piece."
Mercedes will implement a series of updates on its W12 for next week's British Grand Prix, but Hamilton doubts the changes will allow him to bridge the performance gap to Verstappen.
"These past races have been difficult and obviously he’s pretty much just cruising ahead, so there’s not really much I can do about that," Hamilton said in Austria.
"We have a little bit coming, but it’s not going to close the gap enough. So we’ve got to do some more work.
"I’m praying for a different scenario in the next race? " he added. "But you look at their car, it’s just on rails.
"We’re giving it absolutely everything this past two weeks, I’ve been to the factory each week trying to extract as much as I can from the car.
"Our car just doesn’t go well here for some reason. I really hope that it does in these next ones."