Well I would look at the simple stuff first such as spark and fuel pressure. Make sure all of the normal tune up items are taken care of such as plugs, wires, fuel filter, etc. Look at the fuel pressure and make sure that is up to spec. Also make sure the check engine light isn't on and there aren't any trouble codes stored. If everything with the fuel system looks ok then I would look at possibly an intermittent problem with either the camshaft position sensor or the crankshaft position sensor. The Cam sensor should be located on the lower right of the engine, above the crank pulley. The Crank sensor should be located behind the right side of the crank pulley. There could be an issue with the wiring for either sensor as well that is causing the vehicle to intermittently shut off. I would check this things and then go from there. It is hard to directly pin point the problem without doing some testing especially when the problem does not happen all the time. I hope this information helps. Thanks.MikeB8539572.4781901273