SQ7 Fuel Pressure Issues Causing Rough Running & Stalls

Having similar issues with my 2018 SQ8. The symptoms you describe match exactly what I experienced, rough idle, engine misfire, and jerky acceleration. After some initial troubleshooting, the workshop found a loose connection in the wiring harness connecting to the fuel pressure sensor. The intermittent connection was causing incorrect readings, making the engine management system adjust fuel delivery incorrectly. Total repair cost was 95 Euro, mainly labor for diagnosing and fixing the connection. To correctly diagnose your issue and compare with my experience, could you share: Current mileage, When the symptoms first appeared, Whether the check engine light is constant or intermittent, If the problems are worse when the engine is cold or warm, Any recent fuel system maintenance The fuel injector system in these engines is quite sensitive to pressure fluctuations, so proper diagnosis is important. A faulty sensor or connection can definitely cause these symptoms, but its worth confirming with proper diagnostics before replacing parts. Based on my medium experience with these engines, I recommend having a professional scan for error codes and check the wiring connections before replacing the sensor itself.

Thanks for the replies. My mileage is 157016 KM and I had the last service just 2 months ago. The check engine light started flashing intermittently about a week ago, mostly when the engine is cold. The engine stalling and rough running is definitely worse during the first few minutes after a cold start. I checked the service records and no fuel system maintenance has been done besides regular fuel filter changes. The symptoms seem very similar to what you experienced. Before taking it to the workshop, I will have them specifically check the wiring harness and connections around the fuel pressure sensor. The relatively low repair cost in your case is encouraging, as I was worried about having to replace the entire fuel delivery system.

Thanks for providing those details. Having gone through this myself with my SQ8, the cold-start symptoms you describe strongly suggest a fuel delivery issue, just like mine. The mileage and service history you shared actually helps narrow things down. Since you had recent service but no specific fuel system work, and the problems mainly occur when cold, this matches the pattern of a wiring issue affecting the fuel pressure sensor readings. When my SQ8 had these issues, I noticed the rough idle and stalling improved once the engine warmed up. This happens because the fuel injector system can somewhat compensate for incorrect pressure readings at higher operating temperatures. My repair involved: Complete fuel system diagnostic scan, Inspection of the wiring harness near the fuel pressure sensor, Testing sensor connectivity at different temperatures, Repairing corroded wiring connections The total repair still came in under 100 Euro. The fuel pump and injectors were perfectly fine, it was just the system getting incorrect pressure readings due to the faulty connection. Best to have them check the entire fuel delivery system while they are at it, but based on the similarity to my case, I would bet on finding a wiring issue rather than a failed sensor or pump.

Thanks for the input. Just wanted to update on my SQ7 situation. Took it to the workshop today and shared the information about checking the wiring harness. Turns out the check engine light and stalling issues were indeed caused by a damaged wire connection to the fuel pressure sensor. The mechanic found corrosion at the connector, similar to what was described. The intermittent connection was causing incorrect readings, leading to the engine stalling and rough running. Total repair cost was 85 Euro, which included cleaning the connector, replacing some wiring, and running a full fuel system diagnostic. The engine now runs perfectly smooth, even during cold starts. No more stalling or jerky acceleration. For anyone else experiencing similar symptoms, definitely have the wiring connections checked before replacing expensive fuel system components. The fuel injector system works fine once it gets the correct pressure readings from the sensor. Really glad I asked here before authorizing more extensive repairs. Will keep monitoring the engine performance, but so far everything points to a complete fix.