Know nothing about your car as not enough information given, so 1111st thing I would do is put it in to a garage and get a service done on it, oil and filter change, air filter change, fuel filter, basic stuff, if you don't know it's history start at the beginning could be job done easy peasy.DO IT ANYWAY NEVER TRUST WHAT THE PREVIOUS SELLER TOLD YOU UNLESS HE IS YOUR DAD!
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cars.