That is very similar symptom to wife's e53 when the FPR o-ring failed (40¢ part).

Rent or buy a fuel pressure gauge and test the pressure.

If the pressure "jiggles" eg bounces bewteen 49-50 (usually so fast makes the needle fat/fuzzy looking) FPR not working properly.

Other symptom is pressure won't hold.

If pressure drops after power off and is zero overnight it's almost for sure FPR.

That said, fuel pump avg life is 5000-6000 hours. divide odo by 5500 and compare to your average mph. If your mph avg is lower than that # your pump is over due for failure.

The FPR's job is to disguise a failing fuel pump.

At end of life for the last year or two the fuel pump gets weaker and weaker and that is completely masked by the FPR.

Eg: new pump may output 60 psi, the engine gets 50 and 10 goes back to the fuel tank. When the pump is almost dead it will output 52 psi and 2 goes back to tank and 50 goes to the motor.

You may see power loss at WOT when the pump output drops below 50 so the engine can't get 50.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)