Usually during hard acceleration the car cuts out for about 1/2 a second and then immediately regain full power after pressing on the pedal. this problem is intermittent.
This sounds like a fuel delivery issue. When was the last time the filters in the fuel line were changed? Also put an additive in the tank on the next fill up to do a injector cleaning. See if this helps. You may need to have the fuel system serviced. It is expensive, but after two years of getting better gas mileage you will start to get the money back. Does the car have a rev limiter system? Will you reach red line limits? It may cut off the electrical or fuel system until it will be safe to re connect to stop the engine from over revving.
Search Mercedes-Benz CLK-Class Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Mercedes-Benz CLK-Class Experts