Hi everyone, new to this. I have a 99 Subaru legacy GT limited, 2.5 L. Recently it began to idle low and die when stopped. It was fine while actually driving. We changed the fuel filter, fuel pump, and air filter. Now, the car starts, but won't stay running. It dies after a few seconds. The check engine light is on and the code that came up for that was the knock sensor, but from what I've read, it doesn't seem like the knock sensor would cause it to not stay running. Any ideas would be appreciated.