Car shuts off and then drives normally

This is probably the weirdest thing that has happened to my car. Sometimes when I turn on the car it just shuts off. Other times it shuts off when I come to a stop. I have noticed that when it doesn't shut off is when I keep it accelerated. The check engine light comes on and feels like its going to die. I have recently changed the ECU. I noticed it has been acting up like that afterwards. It does drive a whole lot better than before though. These are also some of the recent changes I have done.

Oil change and filter
egr
O2 sensors
PVC
PVC valve hoses
vacuum hoses
spark plugs and wires
fuel filter
fuel pressure regulator
put a fuel injector cleaner in the tank
fuel pump
air filter
coolant temperature sensor
idle control valve
intake air temperature sensor (IAT)
intake manifold gaskets
seafoam
brake booster hose

Thanks in advance