Engine shuts off when transmission is shifted into drive

It has had the transmission rebuilt and a lot done to the motor. It has been sitting for awhile now cause it won't go. It will start every time you crank it and ideals good. When you put it in drive it shuts off every time. The spark plugs where changed, the coil packs where changed, transmission filter was changed also. Just can't figure it out. It can be jacked up off the ground just a hair and it will go but as soon as you let it down it shuts off. Someone said the torque converter, but we don't know. Then we noticed a ground wire unhooked from something in the driver side rear above the tire and do not know what it goes too.