I recently bought a 1994 Volvo 440GL, 110,000 kms (about 65,000 miles), manual 2 litre. Car moves fine from a standing start, and moderate acceleration is unproblematic. But when I try to accelerate hard in third, fourth or fifth gear, the engine races but the car only accelerates slowly, even though the clutch is fully out. After five or ten seconds, rpms and car speed sync up, and everything proceeds smoothly until I step hard on the accelerator again. Do I need to replace the clutch? Or is it something else? Thanks.