If your vehicle is showing engine stalls or dies immediately after starting, here are the most likely causes and the parts you'll need to fix each one.
If the MAF sensor is dirty or was left unplugged after checking the air filter, the engine computer cannot measure incoming air. It will start briefly on a pre-set fuel map and then stall.
If the vehicle doesn't recognize the chip in your key, the security system will allow the engine to start for 1-2 seconds before intentionally cutting off the fuel injectors to prevent theft.
The Idle Air Control valve or electronic throttle body manages the air needed to keep the engine running at idle. Heavy carbon buildup chokes off this air, causing a stall as soon as you let off the key.
A disconnected PCV hose or blown intake gasket lets unmetered air into the engine. This creates a severely lean condition that the engine cannot sustain at idle.
The engine may start on the residual fuel pressure sitting in the lines, but a failing fuel pump or clogged filter cannot supply enough continuous fuel to keep it running.
The Exhaust Gas Recirculation valve should be closed at idle. If carbon chunks hold it open, exhaust gases flood the intake manifold, suffocating the engine immediately after startup.