McLaren drivers Lewis Hamilton and Jenson Button are optimistic that their team will be back on the pace for Saturday in Valencia after a difficult free practice day for the European Grand Prix.
Neither McLaren made it into the top 10 in second practice, with Button 12th and Hamilton 14th. Both drivers were troubled by front brake locking and set-up problems.
"I haven't been happy with the car at all today, but you can't always get it right," said Hamilton.
"I think this year we've been pretty good at getting the balance right throughout practice on Friday and having nice smooth days. Today's just not been one of those days.
"I think we know what the problem is, so I've just made all the changes and I'm quite confident that overnight we'll rectify the issues that I had today and tomorrow will be better."
Button said he was more concerned about race pace than qualifying potential, and suspected that changes made to try and alleviate the brake locking had caused problems elsewhere.
"I think on one lap we're not too bad. We're not great, but we're not too bad," said Button. "But the long run is the strange area for us because the car doesn't feel too bad, but the time just isn't there. We've got to look at the reasons for that.
"We did do a lot of work through the day to improve the front locking, and sometimes when you do that, the balance can become a little bit lazy, so we think that's probably the issue.
"We're going to go back on a few things that we've changed through the session, to a car set-up that we know felt comfortable, but it's difficult to be consistent because of that front locking.
"We know there are a couple of other things that we're thinking about doing for tomorrow morning that are quite interesting."