I drive a 2007 Polo Match in a warm climate. Occasionally, at highway speeds, the car’s engine will suddenly lose power, slowing for a few seconds and then bucks forward and resumes power to repeat many times until I stop and turn off the engine. After a wait it will resume normally until months later when the problem recurs.
You told us almost nothing about your car except the problem so the only answer I can give you is to take it into a trusted independent auto shop for diagnosis. Expect to pay for the diagnosis independent of the repair.