motor has surging poblems on 2000 Chevrolet Express 2500

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?

Asked by for the 2000 Chevrolet Express 2500
code po 340 is cam postion sensor issues,po453 is evap pressure sensor issues and p1870 is trans issues. i would rec a diag from a good mech that can do extensive testing to repair these items.
I agree with#2
1 more answer , 1 more comment
if you can tell us what the codes are we can diagnose easier
I listed the trouble codes in my question,the first time.