The outfit, winner of the past four Drivers' and Constructors' titles, has endured a torrid test period thus far, completing 21 laps over four days at Jerez and only just reaching double figures on the first day in Bahrain.
Vettel, who caused one of four red flags on Wednesday, said: "Obviously we're not happy with where we are and we have a long way ahead of us. The first gut feeling from the car is OK, but we need more running.
"It's not easy to find a quick fix, but I think we understand the problems. We sorted out the issues from Jerez and we did some laps today.
"However, very often you fix one problem and another pops up, which is what happened. That's testing. We all knew this year was a massive challenge and we knew it would be difficult.
"We obviously didn't want this, but it is what it is and we are working flat out to solve the problems."