Idea??

Dear community, remote diagnostics are always difficult – but maybe someone has an idea? For about 6 months, my 2.3 t (125 KW, approx. 180,000 km) has been accompanied by the sometimes occurring phenomenon that short delays occur during acceleration on a distance of approx. 2800 to 3000 UPM, as if “air” were in the fuel line. Does not pass or happen. No matter what external temperatures. Then rest is again and the engine turns up without any problems. he the “lights”: Missing error messages in the memory: also missing. Before I fall on the alarm again my request here. Greetings Jazzer2004