Hello!
I just bought a 2012 XFR with 70k miles. All test drives were great until the day after I brought it home. The car drives fine for normal every day driving, nothing weird, no problems. When I step on it, is where the problems occur. Whenever I'm accelerating hard, two things arise. First, after 5k rpm I feel a lose of power and also I feel the car sort of struggling, it kind of feels like I'm letting go of the gas pedal for less than a moment and then pressing it again, like a slight jolt. That happens everytime, above 5k rpm, no matter the conditions. Sometimes the car will go into limp mode when I accelerate hard, after doing the things I previously said, once I start driving normally it will come out of limp mode. No lights or codes pop up except for the one in the title from a handheld. For some reason the dealer can't get the same code I find with my handheld and they have no idea what it is.... any help?

 

Well if you thread title is true, you need to find out what is causing your low fuel pressure, the AJ133SC has 3 fuel pumps in the XFR 2 high pressure supply pumps on the passenger side of the engine, and 1 low pressure supply pump in the fuel tank. ALWAYS SCAN FOR CODES FIRST!
And start your fuel pressure checks on the low side/supply side, I believe their is a test connection shrader valve for the low pressure side in the driver wheel well behind the splash shield, (If not you'll need some sort of adapter to plug into the end of the supply line on top of the driver side valve cover) . The low pressure supply should maintain 65 psi. If that checks out your gonna need to test the high pressure side, You can read the pressure in the high pressure side using an app like Torque providing your high pressure sensor is good, the pumps output should easily reach a max of 2175 psi when you goose the gas.