ok I have an ses light on with the code p0449 evaporative purge valve solenoid malfuntion. was told the replace the solenoid. I did that today and cleared the code with my scan too. Light went out but when I started it again about an hour later the light was off when I first started it but about 30 seconds later It came back on with the same code. my question is, is there something else wrong or do I have to drive it for a while for it to register before the light will stay off...