At first my car idled high, at around 1,500 RPMs, while in Park or Neutral. Now, the car starts, but then stalls immediately. Could it be the throttle body, EGR valve, or even a vacuum leak?
At such a high idle speed, a large vacuum leak would be possible if the engine didn't return to a normal level after warming up. The idle air control valve regulates engine speed when the throttle plate is closed, allowing air to maintain idle speed. A blockage, or malfunction here can cause your concern. Have a technician, such as one from YourMechanic, run a diagnostic on your engine's high idle speed.
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