You mentioned that they washed the engine ? While doing the service in the engine compartment water might have accumulated water into spark plug chambers or accidentally knocked a spark plug wire loose, what you have to do is start the engine keep it for 1 minute and open up the engine bay and disconnect each spark plug wire from the plugs individually and see if there is a sudden jerk on the engine (Vibration) keep doing it too all the plugs and if there is a issue with one of the plugs the engine wouldn't change a beep after finding the faulty section take off the wire and re fit it and try to drive around and see if it is still rides crappy.