4g63 running issues. runs rough and revs up and down

I did and direct engine swap in my 1991 mitsubishi mighty max. engine is a 4g63 2.4l. did a new timing belt and water pump before i set motor in. When i start the engine it runs very rough and only runs for about 30 seconds. The engine will run at low rpm then surge to a higher rev over and over again for thirty seconds. then on downside of the last surge of rpms the engine will spin backwards and die. i have triied playing with the distributor and that hasnt changed anything. looks like i have everything connected correctly. i am stumped. driving me nuts. anyone have any ideas?

2.0 is a 4G63 2.4 is a 4G64 need more info on the install what parts did you transfer to the new motor ????

yes sorry. messed up on motor when typing. didnt transfer any. just did a new water pump and timing belt. other than that the motor was a complete unit. had everything on it