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?

by in Costa Mesa, CA on November 28, 2012
Get Your Car Fixed at a RepairPal Certified Shop.
We certify shops based on expertise, quality work, and verified customer reviews
2 answers 2 comments
ANSWER by , November 28, 2012
if you can tell us what the codes are we can diagnose easier
COMMENT by , November 29, 2012
I listed the trouble codes in my question,the first time.
ANSWER by , November 29, 2012
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.
COMMENT by , November 29, 2012
I agree with#2