p1211 code

[gjgibson]

Hey everybody,
I have an 01 PSD that has recently begun to run bad. It will drive fine for about 30 minutes. It seems once it warms up it starts acting like it is running out of fuel. the injectors will clatter and it will shudder. I can pull to the side of the road and let it idle for a few seconds and it will smooth out. I will start out again and it will do the same thing before I get through the gears. It has been throwing a p1211 code for a long time but it has been running fine. The code is still there and now its running like crap. I have replaced the fuel pump and have dropped and cleaned the tank so I don't believe it is a fuel supply problem.
Will the P1211 problem cause the truck to run like this?
Regards,
Jeff