I have a 1999 chevy malibu and it jumps when i put it in gear but then some times it acts normal for a few days then starts jumping again when i put it in drive some times.

Are you letting the vehicle warm up and idle down? Do you hear a clunk? If so might be bad u joints or axles or bad Engine mounts. Open the hood and look at your engine, And have someone apply the brake and pop it into gear slowly and reverse and back again several times. If you see excessive engine movement? You have a busted motor mount or mounts.

Check the engine mounts with the hood open. Have an assistant observe from the side if any of them are loose when putting the engine in R or D with the parking brake and hydraulic brakes on securely. If the engine mounts are good, they will not allow the motor to twist inside of the engine compartment very much, not more than an inch or two, and good engine mounts will not allow any clunking to occur when putting the car into 'gear.'