I have been having issues with my 02 Ford Focus ZTS. It has always had an issue with the check engine light staying on (does not flash, stays on solid) since I bought a year ago. It has now developed a problem of sputtering while accelerating and then stalling out after 10-15 min of driving. It is also has started to have a rough idle.
If you are near an Autozone, ask them to check the codes for you. They may be able to identify a specific problem. The sputtering under load is probably related to the rough idle, and suggests that the problem might be related to a single cylinder misfire. But that doesn’t explain the stalling. Most likely you need a fuel pump, which can be tested to see if it supplying enough gas and pressure. There is even a test you can do yourself, which won’t tell you if you have weak fuel pump, but will tell you if the pump periodically stops working. The next time the car stalls, remove the gas cap and have someone turn the engine over. You should be able to hear the whine of the pump. If you hear nothing, the pump is your problem. If the body near the fuel pump is rotted through, and if the problem with stalling occurs only during wet weather, cover the rot with duct tape and see what happens. The pump will fail if it gets wet, at least until it dries.
There are more than a few things that might be causing your problems, though.