Hello my Hyundai Santamo Jg. 1999 Motor G4CP has for some time been less and less power. Meanwhile the vehicle was in the garage to check the timing belts markings. It was also changed. But the problem persists. Uphill brings the still max. 40 km/h. Up to approx. 3000 1/min everything feels normal, and then from this speed you feel a real break-in. It feels like if something closes in the exhaust. But also the two cat were already controlled. I am grateful for every type. Thanks