Sluggish Vitara with Rich Fuel Mix Needs Diagnosis

Had similar issues with my 2003 Suzuki Grand Vitara. The symptoms match what I experienced, poor acceleration, excessive fuel consumption, and uneven running. The main problem turned out to be faulty fuel injectors that were causing an incorrect air-fuel ratio. The diagnostic scan revealed the fuel injectors were not atomizing fuel properly, leading to incomplete combustion. The oxygen sensor readings were all over the place, confirming the rich fuel mixture. The intake manifold also had carbon buildup from the poor combustion. This required professional attention, the fuel injectors needed complete replacement along with cleaning the intake system. This is not a DIY job as it requires specialized testing equipment to verify proper spray patterns and injection timing. While initially tempting to try quick fixes, faulty injectors can cause serious engine damage if left unchecked. The rich mixture can wash down cylinder walls and contaminate engine oil. Would suggest finding a shop that specializes in fuel injection systems, they should be able to properly diagnose with injector flow testing. The repair resolved all symptoms, restored proper acceleration, normalized fuel consumption, and eliminated the check engine light. Plus the engine ran noticeably smoother once the air-fuel ratio was correct.

Thanks for sharing your experience with the Grand Vitara. My Vitara had really similar problems last year. The fuel injectors replacement definitely made sense in your case. I ended up also needing a new catalytic converter since the rich fuel mixture had damaged it over time. The air filter was completely clogged too which made the whole situation worse. Just curious, do you remember roughly what you paid for the fuel injector replacement? And has everything been running smoothly since the repair? Would be good to know if any other issues popped up later.

Yes, the injector replacement sorted out all the rich mixture problems completely. Cost was 515€ for replacing the faulty injection valve, which included diagnostic testing to confirm proper fuel spray patterns. The repair eliminated the poor fuel economy issues and restored normal engine performance. The oxygen sensor readings normalized, showing the air-fuel ratio was finally correct. No more sluggish acceleration or rough running. For peace of mind, I had them clean the intake manifold while they were at it since carbon deposits can build up from running rich for extended periods. Everything has been running perfectly for the past 8 months, no check engine lights or other issues have emerged. Good call on replacing your catalytic converter too. A rich fuel mixture can definitely damage cats over time when the excess fuel causes overheating. Regular maintenance checks help catch these fuel system problems before they cascade into bigger repairs.

Thanks for all the feedback. After putting it off for too long, I finally took my Vitara to a specialized fuel injection shop last week. The mechanic found multiple issues, not just the clogged air filter but also two faulty fuel injectors causing the rich mixture. Total bill came to 680€ including parts and labor. The difference in performance is incredible. No more check engine light, smooth acceleration, and my fuel consumption is back to normal. The intake manifold cleaning they recommended really helped too. Should have done this months ago instead of trying cheaper fixes that didnt work. Learned my lesson about finding a proper specialist rather than going to general repair shops that missed these issues before. The diagnostic testing they did on the fuel system found problems the other places missed completely. Worth every cent to have it running properly again.