LONDON, England - Team boss Franz Tost has admitted Toro Rosso is in the dark just two weeks before Formula 1's 2014 season-opener in Melbourne.The crisis suffered by Red Bull has been in the spotlight but junior sister team Toro Rosso has also been almost completely unable to test its new car amid engine partner Renault's troubles. Tost said: "It's difficult to assess because we have hardly been able to drive. Performance and the reliability are unknown."SOME PROBLEMS SOLVEDTost told Germany's Speed Week: "The Mercedes factory team is clearly in the lead, followed by McLaren; Ferrari. Williams and Force India have also shown good performance. I have the impression Ferrari has not shown everything yet."He admitted that, compared to the disastrous opening test at Jerez, troubled Renault began to solve some of its problems in Bahrain. Tost said:"The systems started to work. Renault has made progress. The time window for Melbourne is tight but if everything worked in Bahrain there is a real opportunity to catch the Mercedes teams."