Suzuki: Suzuki Vitra 1998, suzuki vitra, straight road

Question
i have a standard vitara it wont go over my drive way which is a hill when it start it wont revout but as soon as its on the straight road it will rev and when i come to a complete stop it wont rev until it picks up momentum

Answer
It's either fuel, electrical or mechanical.  Now the trick is to eliminate two of the three as not causing the problem.  Does it only happen with the engine not warmed up yet?  Is it an auto trans?  Has it been a long time since a tune?  Is the fuel filter fairly new, or many years old?
scotty