Car starts then dies immediately

Symptoms

• Engine fires up for 1–3 seconds then stalls
• May need multiple attempts to keep running
• Idle may sound rough right before stalling
• Sometimes stays running if you gently press the gas

Likely causes

• CommonDirty or failing idle air control valveThis valve manages idle airflow; when it sticks, the engine can't sustain idle.
• CommonVacuum leak in a hose or gasketUnmetered air entering the engine throws off the fuel mixture needed to idle.
• PossibleWeak fuel pump losing pressure quicklyThe engine can catch on residual pressure, then die once pressure drops.
• PossibleDirty throttle bodyCarbon buildup can restrict the small amount of air needed at idle.
• Less commonFailing crankshaft position sensorAn intermittent signal can let the car start briefly, then cut spark or fuel.

What to do

1. Try starting again while gently pressing the gas pedal slightly to help the engine hold an idle.
2. Listen and look for a hissing sound or loose hose around the engine, which can indicate a vacuum leak.
3. Check that no aftermarket or recently serviced components (like an air intake) were left loose or disconnected.
4. If the car has a check engine light, note whether it comes on before it stalls; this can help a shop narrow it down.
5. Try again after 10 minutes; if it starts and stays running once warm, an idle control or sensor issue is more likely.
6. Have the throttle body inspected and cleaned if it hasn't been done in a long time.
7. Get a mechanic to check fuel pressure and hold, and to scan for stored trouble codes even if no light is on.
8. Avoid repeated hard cranking attempts, which won't fix an idle or vacuum issue and can drain the battery.

Tools and parts

• OBD-II code reader (optional)
• Flashlight

When to call a pro

If it keeps dying and you can't find an obvious loose hose, a shop can smoke-test for vacuum leaks and check idle control and sensor data.

Safety