Recently got my head gaskets replaced, head work, studs, new oil cooler, full EGR delete, new stg 1.5 KC turbo, and Atlas 40 FICM tune. I'm also running Matt's SRL tune. I have stock injectors with less than 15k since replacement due to a FICM issue. My fuel pressure is fine idling and cruising with pressure in the low to mid 60's psi (have the blue spring mod). Moderate acceleration fuel pressure drops to around 55 psi but holds and immediately comes back up when backing off the go pedal. However, when I drop the hammer the pressure slowly drops and then suddenly falls like rock. Once it hit as low as 20 psi before I could back off. The pressure immediately returns to normal levels after letting up on the throttle. I still have the original HFCM with 210k miles. I'm thinking the pump is just worn out and I need to replace it. I've looked at FASS and Air Dog II but am concerned about durability based on my research. The 4G hasn't really been out long enough to know its long term durability. I have Matt's SRL+ and SRL extreme tunes ready to go but am holding off until I get this fuel pressure issue resolved. Now to the question.... Is a good HFCM enough to handle the fuel needs of my setup, including the extreme tune? Would like the input from others before I decide to buy a new one. Or should I bite the bullet and take a chance with the AD II 4G? I have no plans to go larger in injector size by the way.

Thanks in advance for your input.

 

IMO the HFCM should work fine with your setup. Does with mine. The only real difference between our trucks is your upgraded turbo (and I still have the EGR system, but the tune doesn't use it).