Tonio Liuzzi has said he doesn't feel the F-duct fitted to his car is working to the same extent as that fitted to the machine of Force India team-mate Adrian Sutil.
The team introduced the part earlier this season but Liuzzi said he didn't feel he was getting the full benefit of the part.
The Italian has struggled to match the performance on Sutil on his return to the sport this season and has managed just 13 points, compared to 45 for the German – leading to question marks over whether or not Liuzzi will be in a race seat next season.
“It's not working as it should for me,” Liuzzi told Auto Motor und Sport
of the F-duct. “In terms of top speed I'm generally slower than my team-mate.”
Speculation continues to suggest that Liuzzi could be without a drive at the end of the year, with reports having suggested that test driver Paul di Resta could be promoted into a race seat for 2011.