Hey I have a 2002 wrx and it has not had a single issue until last week. Some issues arrived. First the car died while driving without any signs of hesitation, I pulled over and tried to start it and it turned over but wouldn't run. I let it sit for a while and eventually it started but had a very rough idle and would die if I wasn't on the gas. Eventually it sputtered and died and wouldn't start again blah blah tow truck blah blah. The final diagnosis was the big brown plug between the battery and washer fluid resivour. One of the wires is pulled out slightly and is causing a bad connection. I have heard this is a common issue but I do not know a real fix for it. I can push it back in and it drives fine until I hit a bump and then it just dies again

No after market engine mods what so ever

 

Bypass the multi plug connector for that wire until get a proper fix.