And...

If it is not your cold start valve that is leaking or staying on too long then it could be your fuel pressure regulator has failed. This would allow more gasoline to reach the cylinders than is necessary and give you the same results as a leaking cold start valve.

There are a lot of things to check on this system and they all must work as they should, but it is easy to check them one at a time.

It is, though, time consuming.