What can be the cause that my car jerk and accelerate by itself?

Most vehicles will jerk if there is a misfire or vacuum leak within the engine. To ensure this doesn't happen, get your spark plugs and wires checked after having the computer scanned for any misfire codes. If you have a vacuum leak, it'll need to be fixed as soon as possible. You can usually tell if there is a problem with the acceleration if your car jerks when you first start driving it or if it hesitates when you try to speed up. If you're unsure of what the problem could be, take it to a mechanic and have them take a look.