I have a 93 Chevy 1500 Z71. It started acting up when it got warmed up to normal running temp and it would shut off. I pulled a motor from a 90 Chevy Z71 that I had and knew the motor was good in it. I swapped the motors and now the 90 motor is going the exact same thing that the 93 motor was doing. It will idle all day long even at normal running temp. But once I start to drive it and I stop at a stop sign it dies and won’t start back. I have to let it stir for a while before it will crank back up. It also has a newer fuel pump on it that it about a year old.

Any suggestions?