Cadillac SRX Stalling Issues Linked to Fuel Quality

I had a comparable issue with my 2013 Cadillac CTS last winter. Having some experience with fuel system problems, I initially thought it was contaminated fuel too, but it turned out to be a faulty wiring connection to the fuel pump sensor. The symptoms were very similar, stalling at idle and engine warning light. I tried using fuel additives first, thinking it might clear up potential fuel system contamination, but the problem persisted. After taking it to the workshop, they diagnosed a damaged wire connection to the fuel pump sensor. The repair included replacing the connection and checking the entire fuel system to ensure no other components were affected. Total cost was 95€ for parts and labor. Before jumping to conclusions about wrong fuel though, what fuel grade are you typically using? Does the problem occur right after refueling? Have you recently changed fuel stations? Can you share the specific error codes from the scan? These details would help determine if its truly a fuel quality issue or possibly something similar to what I experienced with the wiring. Consider getting the fuel system properly diagnosed, sometimes what seems like a fuel quality problem can actually be an electrical issue with the fuel delivery components.

Last service was at 121501 KM. The fuel mixture definitely seems off since the engine knock started getting worse. After running several tests, I found the error codes P0171 and P0174 which point to a lean condition in the combustion chamber. Initially suspected contaminated fuel too, but adding premium grade fuel and additives didnt help. The workshop quoted 450€ for a complete fuel system cleaning and diagnostics. Not sure if I should go ahead with that or try troubleshooting further. The engine knock is most pronounced during cold starts and idle. Would appreciate if someone who resolved similar symptoms could share their experience before I commit to the repair.

Thanks for the update and error codes, those lean condition codes actually match what I experienced with my CTS before discovering the wiring issue. While my initial thought was also fuel contamination, the lean condition combined with engine knock pointed to air-fuel mixture problems. In my case, the faulty sensor wiring caused incorrect fuel trim readings, making the system run lean. The workshop quote of 450€ for fuel system cleaning seems high considering the symptoms. Before spending that much, I would suggest checking: Mass airflow sensor connections, Vacuum leaks around the intake, Fuel pressure readings, Oxygen sensor functionality The cold start issues you mentioned are particularly telling, this was exactly how my problems manifested before finding the wiring fault. The engine knock during cold starts is typical of a lean condition, rather than just poor fuel quality. Since adding premium fuel and additives didnt resolve the issue, this further supports that its likely not a fuel contamination problem but rather a component in the fuel delivery or air intake system thats malfunctioning. Based on dealing with nearly identical symptoms, I would recommend getting a second opinion focused specifically on checking the sensor connections and fuel delivery components before committing to an expensive fuel system cleaning.

Based on all the testing and advice, I believe the issue goes beyond fuel quality. The error codes P0171 and P0174 combined with the persistent engine knock, even after trying premium fuel and additives, suggest a deeper problem with the fuel delivery system. While the wrong fuel or fuel contamination was my initial concern, the symptoms point more toward a system malfunction, especially given how the engine behaves during cold starts. The lean condition codes are particularly concerning. The 450€ quote for fuel system cleaning seems expensive, but before making that investment, I plan to have the following checked: MAF sensor connections, Vacuum system for leaks, Fuel pressure readings, O2 sensor operation The fuel mixture problems during cold starts make me think the previous responder might be right about checking the sensor connections first. Since the last service was at 121501 KM, its worth investigating the electrical components before assuming its just bad fuel quality. Will get a second opinion focusing on these components rather than jumping straight into an expensive fuel system cleaning. Will probably also replace the fuel filter while Im at it, since that could contribute to the lean condition.