Hybrid Passat Stalling: Fuel Regulator Investigation

Had similar issues with a 2019 VW Passat GTE. The check engine light came on after changing the fuel filter, followed by rough idle and significant power loss. Initially suspected the fuel pressure regulator, but diagnostic testing revealed a bigger problem. The issue stemmed from incorrect fuel filter installation causing a pressure drop in the fuel system. This triggered the engine management system to reduce power output. The fuel pump was also struggling to maintain proper pressure due to a partially blocked filter housing. The fix required: Proper realignment of the fuel filter, Cleaning the fuel pump assembly, Resetting the engine management system, Testing fuel pressure at multiple points, Verifying proper idle control This was a serious issue that could have damaged the fuel injection system if left unaddressed. The rough idle and power loss symptoms matched perfectly with a fuel delivery problem. After the repair, the check engine light cleared and normal performance returned. Make sure to find a shop familiar with hybrid fuel systems, as they require specific diagnostic approaches due to their dual power sources.

Thanks for the detailed reply. Your symptoms match exactly what I experienced. I definitely had the same engine misfire and rough idle issues. The mechanic found similar problems with the fuel rail and pressure sensor readings being way off. Glad to hear your fix worked out and good tip about finding hybrid-experienced techs. Did you remember roughly what the repair cost? Also curious if youve had any other fuel system problems since getting it fixed?

After getting the fuel pressure regulator replaced, the car runs perfectly now. The check engine light and rough idle issues completely disappeared. My total repair came to 45€ to clear the error codes after the fuel filter change. Much cheaper than I expected given all the initial symptoms. The fuel efficiency has actually improved since the fix, and I havent experienced any other fuel system problems in the past months. The fuel rail pressure stays consistent now, and the engine runs smoothly even during cold starts. Getting the right diagnostic work done by a qualified technician made all the difference. Just make sure your mechanic properly tests the fuel pressure and system integrity after any repair. A proper fix should completely resolve the rough idle and power issues youre experiencing, not just mask the symptoms.

I got it checked out at a new shop yesterday and the diagnosis matched exactly what you described. The mechanic found low fuel rail pressure and a failing pressure regulator that was causing the rough idle. The shop specializes in hybrids which really helped, they knew exactly where to look. The total repair came to 780€ including parts and labor. Not cheap but worth it to have the car running properly again. They did a full fuel system pressure test afterwards to confirm everything was fixed. The engine runs smooth as silk now, no more stalling or power loss issues. Makes such a difference finding the right shop that actually knows what theyre doing. The previous mechanic completely missed these fuel delivery problems. Really appreciate the detailed advice, it helped me push for the right diagnostic checks this time around.