GMC Acadia Stalling: Fuel Pressure Issues Decoded

I had a very similar issue with my 2014 GMC Terrain last year. As someone with basic car maintenance experience, I was initially puzzled by similar symptoms after changing the fuel filter. The problem turned out to be related to the fuel pressure regulator, which wasn't maintaining proper pressure in the fuel rail. After getting a diagnostic scan, it showed the fuel system was struggling to maintain consistent pressure, causing engine misfires during acceleration. My workshop identified that the fuel filter replacement had introduced air into the fuel system, requiring a proper bleeding procedure. They also checked the fuel pump operation and pressure readings at the fuel rail. The total repair cost was 45 Euro, which covered the diagnostic and system bleeding. Before suggesting specific fixes, could you share: Current mileage on your Acadia, Whether any recent fuel system maintenance was performed, If the check engine light is steady or flashing, Any specific error codes from the diagnostic scan This information would help determine if your issue matches what I experienced or if it might be something else in the fuel delivery system.

Thanks for sharing your experience. I have not performed any recent fuel system maintenance. The check engine light remains steady, not flashing. My Acadia has 78332 KM and the diagnostic scan shows error code P0171, system too lean. The rough idle seems worse when the engine is warm, and fuel efficiency has dropped noticeably over the past few weeks. The engine misfire is most noticeable during acceleration, as mentioned. I am concerned the fuel pump might be failing, but your input about the fuel regulator issues is helpful since the symptoms match closely. I will have the fuel pressure tested at idle and under load to pinpoint whether its the regulator or pump causing the problem. Did your repair process also involve pressure testing?

Yes, pressure testing was crucial in diagnosing my Terrain's issues. The P0171 code you mentioned typically indicates a lean fuel mixture, which matches the symptoms I experienced with the faulty fuel pressure regulator. The fuel rail pressure test showed significant pressure drop during acceleration, confirming the regulator wasnt maintaining proper fuel system pressure. The interesting part was that the pressure variations became more noticeable as the engine warmed up, similar to what youre experiencing. While my initial concern was also the fuel pump, the diagnostic revealed the fuel pressure regulator was the primary culprit. The technician connected a fuel pressure gauge to monitor readings at idle and during acceleration. At idle, pressure would start normal but gradually decrease, leading to the engine misfire and rough running. Key findings from my repair: Fuel rail pressure showed inconsistent readings, Engine misfire occurred mainly during pressure drops, Warm engine conditions worsened symptoms, Replacing the pressure regulator resolved all issues The complete fuel system inspection and regulator replacement ended up costing 180 Euro, but prevented potential damage to other components. Given your similar symptoms and error code, I strongly recommend getting the pressure tested before replacing any parts.

Thanks everyone for the detailed responses. After reading about your experience with the fuel pressure regulator, I feel more confident about the direction to take. The symptoms you described with your Terrain, especially the pressure drops during acceleration and worsening conditions with a warm engine, match my situation exactly. I will schedule the fuel rail pressure testing this week. The steady check engine light and P0171 code, combined with the rough idle and engine misfire issues, strongly suggest fuel delivery problems just like in your case. Really helpful to know that the pressure testing revealed the true culprit in your situation. If the fuel pressure regulator turns out to be the problem rather than the fuel pump, the 180 Euro repair cost seems reasonable to resolve these symptoms. I will update once I have the pressure test results and know more about what exactly is causing the lean condition. The detailed diagnostic approach you suggested should help pinpoint whether its the regulator or other components in the fuel delivery system.