High idle then engine shuts off

Hello,

A high or surging(idle that is searching up and down) is usually caused by a vacuum leak, but sometimes can also be caused by a faulty Idle Air Control valve (IAC). 9 out of 10 times though it is a vacuum leak. By vacuum leak I mean any unmetered air entering the air intake system anywhere from the Mass Airflow Sensor(MAF) to the engine's combustion chambers. Unmetered air is air that is not accounted for by the MAF. Here is a link below for you to go to:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

A good way to check for a vacuum leak is to get a propane torch, and with your vehicle idling, crack the torch open to it's lowest setting. Do not light the torch, just have it leaking a little propane. Run the torch along the air intake duct, intake manifold, inside where the engine valley is as well as outside, EGR Valve, vacuum lines, and Evap hoses, paying close attention to the intake manifold. Where ever the leak is, when the torch passes by it, the engine will rev up as it ingests and burns the propane. Please go through these guides and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros