assuming its never been in a wreak . and its a new car. im gonna say tires first .run your hand around the circumferance of the wheel on the tread surface. it should be an even surface if not then when it gets to rollin the tire will start hopping. also. the same will happen if the wheels arent balanced , you can check for that by looking at tread wear.its called cupping. . your question was kinda broard . can you try to find if its the front of the car or rear of the car passenger side or drivers side.could be just about anything that rotates. with all the clues you have given i would say tires the tread wear tells a story .if your wife says the acceleration is poor then it could be the engine how does the engine sound? how bout you drive it and then ask the question again.with better details