Fuel rail Px dips hard then recovers?


New Member
Mar 31, 2024
2010 335i auto, has index 12s, year old hpfp, I pulled the tune off to try to determine the cause of my problems but can't find it.

Coming from a stop or a slow roll the fuel rail pressure post hpfp will dip to 500 and remain there for a couple seconds then recover. Lpfp pegs at about 73 and stays there, so i dont think theres an issue there. It doesn't misfire, it doesn't throw a code it just feels like there is 0 power/torque for a bit. I can force it to not do this by giving it more throttle than should be required at that point and then easing off. I know a log would help yall, ill try to get one later today but without one, where would you suspect the problem is? Faulty sensor? Hpfp? Injector issue some how?