89 civic stals when going to an idle
 

I have an 89 civic dx 1.5 m/t that starts and runs fine at an idle but when you go to drive it after shifting a couple of gears and you step on the clutch or come to a stop it stals may or may not start back up. We have replaced the fuel pump. Dist cap. Button wires plugs. Iac is working. Tps checks good. Cant find any vac leaks. You can hear the main relay working. What else could it be