92 dohc problems!!!!!!!!!

[chalmer240sx]

alright so i just got done with a 92 dohc swap into my 90 240sx the motor only has 125xxx miles on it and it ran fine for a couple of days then out of nowhere it just crapped out on me. what it does is it doesnt seem to want to stay running. the only way it will is if i sit there and feather the gas, and sometimes it will have problems starting and i have to sit there and feather the gas as well, i think its timing but i dont have a timing light and the dizzy seems to be in the same spot as it was before. not sure what the issue is any help or ideas will be appreciated!