This is just crazy. Word for word it is the exact same as ours. We have a friend that is a mech. and he resets the codes and then it runs fine for about a week. Since I read your thread I have been watching the gas and it has yet to make a difference on how it is running but the rain might have something to do with it. And living in the great NW this could be a big problem!
Thanks, we will keep you informed and hope you will do the same on any changes or "cures" you find.