Symptom guide
Car Stalls at Idle
Common reasons an engine stalls at stoplights or while sitting still.
Quick answer
Idle stalling often points to dirty throttle control, vacuum leaks, purge valve issues, fuel delivery, or sensor errors.
Most likely causes
- Dirty throttle body
- Vacuum leak
- Stuck purge valve
- Weak fuel pump
- MAF sensor fault
Basic driver checks
- Notice whether it stalls after refueling.
- Check if AC load makes it worse.
- Scan for idle, lean, or EVAP codes.
- Listen for hissing near the intake.
DIY diagnostic path
- Inspect intake tubes and vacuum hoses.
- Record fuel trim data if available.
- Do not adjust throttle stops manually.
- Clean throttle body only with correct procedure.
Common mistakes
- Replacing spark plugs for every stall
- Ignoring EVAP purge symptoms
- Driving in heavy traffic with repeated stalling
What to tell the mechanic
Describe whether stalling happens cold, warm, after fueling, with AC on, or when shifting into Drive.