Some of the replies are a little lengthy and I apologize for not reading through them all. If it wasn't mentioned, An important test also would be to see if the engine will fire up again and run after sitting for just a few minutes. If it does then there is a possibility of substantial debris and/or rust in the fuel tank that is sucking up onto and completely blocking the pickup screen in the tank. When you shut the engine off, the suction stops and the debris falls off the screen allowing gas to flow again. This was happening with my generator pickup until we figured out the cause. I hope this information is helpful to you. I will add that one of the most helpful gauges I added to my dash was an electric fuel pressure gauge. The setup I purchased was a simple T fitting, an electrical sensor, and a gauge. It works like a charm and allows me to monitor the fuel pressure at all times, especially when climbing some of the serious grades out west. When climbing steeply out there I have seen fuel pull away from the pick up tube with as much as 1/2 a tank. It has been super helpful.