2003 Dodge neon Replace computer?

My car has now been starting fine with no error codes for almost a week now. Just an hours ago I started it up and the engine light came back on. Its now only 1 error code of P0440 Evaporative Emission Control System Malfunction. But at least it’s still starting, for now.

I can’t help but think since this is such a sporadic error it may be very difficult/expensive to trouble shoot. Which is why someone probably got rid of the car, and I got such a good deal on it.

Any more suggestions are greatly appreciated, and thanx again!

-shawn