Engine problem in idling and acceleration

Hello Scenic friends, have a problem with my Scenic 1.6l 16v bj 99.Started the problem with a restless run in the stand, the speed commutes between 500 and 1500 revolutions ran but as soon as you have given gas clean and powerful.Now today trip with the family made still quickly refueled, up on the highway and after about 30 km down there it started.Takes gas no longer properly has full power, stutters and pulls not really up.1,2,3 everything the same thing I am then in the 4th gear and the rotation fence reaches 2800 turns also in the 5th gear it feels as if it had full power again.As soon as the speed then after braking, so 5th gear again under 2800 falls it stutters again.Don’t get hot.Spring normally.When it is warm commutes rotationally as already written above, it cools off after a few minutes and Will start it goes off in the standing gas until it is warm again you have to hold gas.Who knows the problem or knows what the lead is ns can be.Hab bought the car first,is already the third I have, but did not have the problem yet. I really appreciate about every help.Hoffe described it well. I’m new here I should have made a mistake,please have a look,because in order to find my way around here I need almost a Dr. title. Thanks in advance.Gruss Chris