Newmarket's Michael Caine expressed frustration with his car after a poor start to the 2011 Porsche Carerra Cup.
The 41-year-old, last year's championship runner-up, recorded sixth and seventh-placed finishes in the two Brands Hatch races over the weekend.
"It was incredibly average in fairness, we've obviously got a lot of work to do with the cars," the Motorbase driver told BBC Radio Suffolk.
"We don't have a quick enough car at the moment."
Caine is next in action at Donington Park in two weeks time, and hopes to take an improved car with him.
"We need to do a lot of work to see why we're not in first," he said.
"It's not what the doctor ordered but I'm sure we've got some medicine in the cupboard to make the car recover."