jean paul

its a big noise that was not happening before i wash it the car was very smooth and i could hardly hear even the engine after the 80kmph the noise happens everytime i push gas and goes louder very annoying

i washed the car chassie at the petrol station after the rain and a bit of ofroad just to remove the mud underneath. the day after while driving i hear some noise and some vibration at 80kmph what can that be?