Hesitating when acceleration

My car hesitats to take off from a dead stop. When I take off I have to play with the gas petal til I get to about 15 mph then it start acting fine til the next time I stop. Do you have any ideas what this could be? Also I was having problems when I went about 50 mph and come to a stop my car would jerk and die and wouldn't start back up for about 20-30 mins. This I belive is the toque cluch converter. I unpluged the 4 prong connector going to the tranny. Is this the tcc or a sensor? Plus after my car sits like over night I go to start it and it dies instantly and continues to die til I start it and slam on the gas and rev it up.
I used to have problems with my car hiccuping while I was coasting at a constant speed due to the computer being bad and not alowing the maf to work. I replace the ECM and fixed that problem. Also replaced the maf, a o2 sensor, spark plugs, and wires
Thanks for any help!