2001 Dodge Ram 5.9 surging

ladyroper

I have a 2001 Dodge ram 5.9 turbodiesel during the warm weather ran just fine. I took it up at a higher elevation this last summer where it was cooler started acting like he was starving for fuel had to keep the Excelerator up at a higher RPM for it to run correctly now that winter is coming I am getting the same response out of it until after the motor is warmed up it acts like it's starving for fuel what could be the problem I am thinking a lift pump any and all suggestions would be greatly appreciated

ladyroper

Also no codes are being thrown at this time