Help! Problems with stationary gas and delayed acceleration SKL 200 K. Bj 2000 170tkm

Hello everyone and it’s a good ride. I have a problem with my newly acquired Slk which had the problem when buying. I try to describe it… I start the car in the cold condition, the engine runs normal in the stationary gas. Hardly it reaches a certain temp. ( after the start in the stand after about 4-5 min. ) the threshing number breaks as if it dies immediately, but catches itself and that all the time. I also have a delay at the speed (about 5 sec.) As if the signal from the Pedal delay is assumed. So I thought with a new accelerator the problem would have been fixed but not so today I have a new built-in without improvement. If someone has an idea I would be happy about tips. According to previous owner a new LLM was installed but also without improvement. Greetings -Eddy