I use a mitsubishi Sigma automatic car, whenever i accelerate (on motion) the car jerks during the process of selecting from on gear to another. Please what is likely to be the cause and what do i do to resolve this problem.

most likely ur transmiision/gear box is damaged.

how does it respond on reverse?

possibly sensor issues or bad ATF!

@Rolly
Touch not any of the things mentioned above.
First does the car steam ok on start up, or does the rev meter flutter?
Second does it accelerate well after the initial jerk? You might also do the following
Third check your plugs are all firing well, or change them all .
Fourth, at night open your bonnet and start the car to confirm any current leaks from your plug cables.(These should show as flashes of light in the dark).

Do these and then report back on status.