Conversation Between Rockledge and kybigbluefan

I am getting this same code. My truck just doesn't have any power. Sometimes though it runs fine and just out of the blue it starts losing power and falling on its face. I have changed several parts and still can not find the solution. Also when I am filling up with gas, the gas keeps kicking off like the fuel is coming back up the neck. Someone please help me.
Here are the parts I have changed already.
Fuel pump
Fuel filter
Fuel relay
Idle Air Control
Mass Air Flow
Both Oxygen Sensors
Muffler
plugs
plug wires
I think thats everything. Any input would be greatly appreciated. It's kinda funny cause somedays it runs great and others I can barely pull out and can't pull out on hills because it just doesn't have the power.

Very Confused,
James