BMW Z3 Stalling & Power Loss: Fuel Mixture Mystery

Hey there! I had some experience with a similar issue on my 2003 BMW M3 (I have some basic car maintenance experience, mostly oil changes and spark plugs). Sounds very familiar, my car had almost identical symptoms to yours. The rough idle, jerking, and power loss were really frustrating! Took it to my trusted workshop and turns out one of the injectors was shot. Had to replace it, set me back about 515 Euro but the car's been running like a dream since. The mechanic explained that bad injectors mess up the fuel delivery, causing all those symptoms you described. Before I can help more specifically, what's your mileage and have you checked the codes with a scanner? Also, have you noticed any fuel smell or increased consumption lately? These details would help compare our situations better.

Thanks for sharing your experience! Mine's at 148051 KM and just had its service last month. Those symptoms do sound spot on with what I'm experiencing. Haven't noticed any fuel smell, but definitely burning through gas faster than usual. I'll get those codes checked first thing, that's a smart suggestion. Had no idea a single injector could cause so much trouble, but it makes total sense. Gonna call the workshop tomorrow and mention this. Really hoping it's just an injector issue like yours and nothing more serious. It's not cheap but beats having to deal with bigger engine problems!

Hey again! Just wanted to follow up on this since you mentioned getting the codes checked. Yeah, my M3 was acting exactly the same way when the injector failed, it's crazy how one small part can mess up the whole system, right? When I had the issue, my fuel consumption went through the roof too. I remember calculating it was using about 25% more fuel than usual before I got it fixed. The mechanic showed me the old injector after they replaced it, it was completely gunked up and wasn't spraying properly at all. Since your mileage is pretty close to what mine was when it happened (mine was around 155000 KM), I'd bet money it's the same issue. One thing I forgot to mention earlier, before getting it fixed, I tried cleaning the injectors with some fuel system cleaner, but it didn't help at all. Just ended up wasting time and money on that stuff. Let me know what the codes show up. If it's anything like P0171 or P0174 (those were my codes), then we're definitely looking at the same problem. Keep us posted on what your workshop says!

Thanks for the detailed follow-up! Just got back from getting the codes read and wouldn't you believe it, got P0171 just like you did! it's almost scary how similar our situations are. Really glad I didn't waste money on injector cleaner, was actually thinking about trying that first. Called the workshop and managed to get an appointment for next week. The mechanic seemed to agree that it's likely injector-related when I described everything, especially after I mentioned the codes. Thanks so much for all your help with this, you've saved me tons of time and probably money too by pointing me in the right direction. Will definitely update you once it's fixed. Fingers crossed it's just the one injector and not multiple ones! This is why I love asking for advice from other BMW owners, you guys really know your stuff. Much appreciated!