Engine/Transmission (1998.5 - 2002) FASS DDRp

[BFrye]

Does a FASS DDRp usually loose pressure gradually or quickly? Also does cold weather affect fuel pressure?

 

[JR]

If your drawing through the OEM fuel lines it will drop rather sharply under a load. They are a restriction IMO even in factory horsepower settings. Upgrading to a 3/8 or 1/2 fuel line from the tank up to the VP will reduce the strain on your pump and will keep the pressure a little steadier under heavy engine load. The other favor you could do for your lift pump is relocate it to the frame rail away from the vibrations and heat of the engine. There is good reason they havent had a pump there in OEM trim in almost 10 years....
As for cold weather affecting pressure yes it will but it has to be prett cold, down into the single digits and below in my experiences.