KeremP

Hello everyone, I am having trouble with the p0300 code and wanted to see if anybody has dealt with this problem before. The car starts up fine drives fine until it gets to the higher RPM's and then the code comes up. I have just changed all the spark plugs, wires, and ignition coils but it did not fix the issue. Car is SL55, also recent resonator work was done to the car and this happened a day after. do you guys think it is a coincidence? Thank you all for your help.