Hello, I have a 2002 Ford Focus ZTS. Just the other day I was driving it and running errands. I stopped at about four or five different stores. As I was leaving my last store my car wouldn't stay running. I'd turn it on and the engine would start, but it would then turn off right away. I tried giving it gas, and while I was ******* it, it would stay on but as soon as I stopped the engine would die again. I left the car and went in a store for about 15 minutes and when I returned the car turned on and I was able to drive home fine. It's important for me to note that this same thing happened last summer a few times. Every time I'd let the car sit for 15 minutes or so and it would start working again. I've also noticed that every time it's done this it's on really hot day and it's when I'm making multiple stops. Any ideas of what the problem could be?
Most likely a phenomenon known as vapor lock. It's caused by a combination of low fuel pressure and increased heat in the engine compartment. Find a parts store that will loan you a fuel pressure tester. Locate the fuel rail feeding the fuel injectors. Towards the back of the car will be a valve resembling a tire valve. This is where you attach the pressure gauge. With the engine running, this should be between 36 and 65 PSI. The warmer the engine and fuel rail, the higher the pressure should be, so test it at various temperatures.