Buick Regal GS Fuel and Stalling Issues Need Solutions

Had similar issues on a 1998 Buick Century with the 3.1L engine at 110k km. The main symptoms matched yours, high fuel consumption, rough idle, and power loss. The smoke from exhaust and stalling pointed directly to a faulty fuel injection system. The maintenance revealed multiple issues with the fuel injector connections. The wiring harness had deteriorated, causing inconsistent electrical signals to the injectors. The system was not maintaining proper fuel pressure, leading to uneven fuel delivery and incomplete combustion. This was a serious problem requiring immediate attention, as continued operation could have led to catalytic converter damage. The repair involved replacing the entire injector wiring harness and cleaning the fuel injectors to restore proper spray patterns. After fixing these components, the idle smoothed out completely, power was restored, and fuel efficiency returned to normal. The exhaust smoke disappeared since the engine was getting the correct air-fuel mixture again. These symptoms typically indicate fuel delivery problems, so your mechanics diagnosis likely has merit. Proper diagnosis requires testing fuel pressure and checking injector pulse signals with specialized equipment.

Thanks for sharing your repair experience. I had the exact same symptoms with my 2002 Regal GS last year, rough idle, power loss, and the whole fuel injection system drama. The diagnosis matched what you found, but I am curious about the repair costs since prices vary quite a bit. What did your mechanic charge for the full repair including parts and labor? Also, has the engine run smoothly since the fix, or have you noticed any other fuel system issues popping up?

Happy to report that since getting the repair done, the injection system has performed flawlessly. The fix was actually much simpler and cheaper than expected, just needed to repair a faulty cable connection to the fuel injection component. Total cost came to 95 for parts and labor, which was a relief compared to what I initially feared. The maintenance solved all the symptoms completely. Fuel consumption returned to normal levels, the idle smoothed out, and power delivery is consistent again. The petrol system now works exactly as it should with no smoke or stalling issues. It has been months since the repair and I have not experienced any additional fuel delivery problems or injection system concerns. Regular system checks show everything is operating within normal parameters. This relatively minor fix prevented what could have become a much more expensive repair if left unaddressed. My advice would be to have your mechanic specifically check the electrical connections and wiring to the injection components first, as this can often be the root cause rather than a complete system failure.

Finally got the repair done last week and wanted to share the outcome. Turns out the fuel injection system needed attention but not a complete overhaul as initially suggested. The mechanic found a cracked fuel pressure regulator causing uneven fuel delivery. They also discovered an air leak in the intake manifold gasket which explained the poor idle and stalling. Total bill came to about 350 for parts and labor, much better than the 1200 estimate from the first shop. The engine now runs perfectly with no smoke from the exhaust. Fuel consumption has dropped back to normal and the idle is rock steady. The repair took just under 4 hours and the difference in performance is night and day. No more stalling, better acceleration, and the engine sounds much smoother. Really glad I got a second opinion instead of rushing into the more expensive repair option. Appreciate everyone sharing their similar experiences. It helped me ask the right questions during diagnosis and understand what was actually wrong with the fuel system.