S40 T4 Bj.97 – ESP error, engine jerking

Hello guys. I bought a Volvo S40 T4 a few days ago and I have a few small defects. One of them is that the ESP light is on after starting and does not run out any more. According to the previous owner it should be on the front left – try to let the computer read out today, then I might know more. Other problem is that I can only turn up to 5,000 rpm. If I continue to speed up, it starts to jump like an “ELCH” :O). But no engine malfunction lamp or something like that. I have already thought that it might be on the spur, the previous owner has always filled 95ers, but according to the tank lid has to enter 98ers. Did one of you have the same problem? And can I possibly give a little hint about what it can be? I also thought that the engine might go in emergency run, because the DSA is constantly lit, but the performance is actually there. Thank me already in advance. LG New Elch drivers