car jerks driing down the road, it lunges and jumps it can be small way or radically

It could be many things, unfortunately and without experiencing the problem first hand or being able to do some basic diagnostic tests its hard to say. Is the Check Engine Light on? If so the codes stored in the computer in your car may give an indication as to whats wrong. It could be fuel, ignition or a problematic engine sensor but tests are needed to find out what is wrong.