Hello!!!!!!!!!!!!! I have a little problem with my engine. The driving speed is about 1100 – 1400 rpm. for a tip, the speed to approx. 750 – 900 rpm would be appreciated. Sometimes the speed is correct (approx. 850 – 900 rpm). The engine has a mileage of 115,000 km and was very maintained by the previous owner. ( All inspections). mfg reinhard