Engine stalls in low gear

Engine stalls in low (initial) gear, intermittently. The (current) alarm comes in usually right after starting the car, than I know I am going to have trouble. In first gear only it tends to stall when I first try to move. It will jerk and stall and if I let off the gas it seems to help. The engine does not shut off, just stalls. I might go for days without any problems than it starts. If I turn it off and come back after a while (?) the alarm (and problem) often goes away. I have had it in the shop and they have done many things including replacing the engine computer but it has never been fixed. After they changed the computer it failed about two more times. then there was a long stretch where it ran perfectly but recently has had a lot of failures. almost always show up right after the car is started.