Schumacher frustrated by 'issues'.

If Ralf Schumacher had hoped to impress Force India with his performance in testing on Thursday, he picked the wrong time and place as mechanical gremlins prevented him from getting to grips with the F8-VIIB at Jerez.

The German partnered another 2008 hopeful, Vitantonio Liuzzi, on the third day of action in southern Spain, but the day was interrupted by a combination of lengthy red flag periods and mechanical downtime which disrupted both drivers' programmes, as they had with fellow veteran Giancarlo Fisichella on day one.

Schumacher and Liuzzi both worked to gather data on the 2008 control systems - seeing how the car reacted to changes the precede the ban on traction control and engine braking - as well as general set-up work and tyre evaluation. Neither, however, was able to complete their respective programmes due to the interspersed runs. Right from the start, Toyota refugee Schumacher ran into problems, with hydraulic failure in the morning leading to the team aborting his shorter runs. The German was happier on longer runs, however, with the team impressed by his pace and consistency.

"It was a difficult day as it was my first time with the team and I had to learn about how to work with the 2008 electronics," Schumacher admitted, "Unfortunately, we had some problems with the car in the morning and then lots of red flags in the afternoon but, when we went for the long runs, it was quite promising.

"Unfortunately, we didn't get it right when we had some new tyres on in the morning, and the second try was interrupted by a red flag but, although it was a difficult day, it was still good. I think we got some good information."

"This morning was quite productive as Tonio got a fair few laps in and gave some good feedback, but, for Ralf, it was more difficult as we had some issues with the car which slowed things down," technical director James Key confirmed, "Over the longer runs, however, it came together pretty well for him, and he was very consistent."

Schumacher, like Liuzzi, Fisichella and others, has made no secret of viewing Force India as his only hope of remaining in the Formula One next season after being dumped by Toyota. The German is friendly with new team owner Vijay Mallya following the Indian's sponsorship of the Toyota team, but is not guaranteed the second seat alongside Adrian Sutil.

Roldan Rodriguez, a candidate for the reserve driver role, Christian Klien and Giedo van der Garde have all tested with the team this week, with Sutil having intimated that the Silverstone operation could look towards younger candidates as his partner in 2008.