motor has surging poblems

What is your question?

At speeds of 10 to 20 miles an hour the motor surges up and down,I have codes p0340,p0453,and p1870,the fuel pump pressure is at 60psi when the motor is running or just with the key on,and stays ther when the key is turned off.It is hard to refuel,the gas pump at the service station keeps shutting off.What could cause these problems?