BMW M3 Fuel Injector Symptoms: DIY Diagnosis Guide

Hey there! I can relate to this, had similar issues with my 2011 BMW M5 last season. The symptoms you're describing are exactly what I experienced: rough idle, increased fuel consumption, and poor performance. Turned out my fuel injectors were indeed clogged. Had them professionally cleaned and tested at a specialized workshop. They found carbon deposits blocking the spray pattern. The fix wasn't just a simple cleaning though, two injectors were beyond saving and needed replacement. It was definitely a serious issue that needed immediate attention, as dirty/faulty injectors can lead to bigger engine problems if left unchecked. The repair took about a day, and the difference in performance was night and day. Car runs smooth now, idle is perfect, and fuel economy is back to normal. Would definitely recommend getting it checked soon, these symptoms won't fix themselves and could get worse. Just make sure whoever works on it has proper diagnostic equipment for BMW direct injection systems. It's pretty specialized work, and you'll want someone who knows what they're doing.

Thanks for sharing your experience! That's super helpful, as I'm dealing with pretty much identical symptoms. Really good to know I'm on the right track with the injector diagnosis. Quick question, do you remember roughly how much you ended up paying for the whole job? Also, has everything been running smoothly since the repair, or have you noticed any other issues pop up? Really appreciate the advice about finding someone with proper BMW diagnostic equipment. Definitely don't want to mess around with just any regular shop on this one.

Hey again! Just wanted to follow up on your cost question. After taking my M5 to the specialist, they confirmed it was exactly what I suspected, faulty injection nozzle was the culprit. Happy to report they sorted it out completely! Total bill came to 515 € for fixing the dirty injection valve, which honestly wasn't as bad as I feared. Since the repair, my car's been running like an absolute dream, no more problems or rough starts. Fuel economy is back to where it should be, and that annoying jumpy idle is completely gone. It's been several months now, and I haven't had a single issue pop up. Best decision I made was getting it fixed right away instead of waiting. These high-performance engines really need proper care, and trying to save money by delaying repairs usually ends up costing more in the long run. Let me know how you get on with yours, always interested to hear how fellow BMW owners solve these kinds of issues!

Thanks so much for all the detailed info! Just got back from the mechanic today and wanted to update you. You were spot on about everything! Took it to a BMW specialist who really knew their stuff. They did a thorough diagnostic and found two clogged injectors, just like in your case. The whole job cost me 490 €, pretty close to what you paid. Really relieved it wasn't worse! The difference is amazing. Took it for a test drive and it's like having a new car again. No more rough starts, the idle is butter smooth, and that annoying fuel guzzling issue is gone. The mechanic was super professional too, showed me the old parts and explained everything they did. Really grateful for your advice about going to a specialist. Could have ended up with much bigger problems if I'd waited longer or gone to my regular shop. Thanks again for helping me avoid another costly mistake!