New Focus Having Problems
When I read the title of the complaint I said "how can a "new" Focus have any problems". I didn't know it was 2002. All I can say is either buy yourself a shop manual if you are the DIY type or take it to a shop. SOUNDS to me like the problem is in the tranny. You might also check the transmission fluid level. If the oil is burnt (brownish) or smells that is bad. If it is low then you might try filling it up but don't overfill. If all that fails then I would take it to a transmission shop (not a dealer either). If the car has lots of miles on it or has had a rough life then that is not good either. All mechanical devices have a finite life span. I don't care what it is...they all wear out eventually.
I don't know when the Focus first came out but I would never buy the 1st or 2nd year of any American (economy) car. Don't know if I would even buy the same of any Japanese car either although I trust them far more than the American's. ( no offense to American car owners...just my experience and opinion)