BMW Z3 Rail Pressure Issues: Rough Running and Stalling

Hey there! I had a similar issue with my BMW Z4 (2002) last year. I've got some experience working on cars, mostly basic maintenance and troubleshooting. The symptoms you're describing sound exactly like what I faced. My car was doing the same thing, rough running, terrible idle, and that annoying check engine light. Initially thought it might be the fuel pump, but it turned out to be the pressure sensor. Took it to my regular workshop, and they diagnosed it right away. Had to replace the sensor completely, cost me about 240 Euro for parts and labor. After the fix, the car ran smooth as butter again. Before I can share more specific details, could you tell me if you've had any diagnostic codes read? Also, when did these symptoms first start, and have you noticed any differences in fuel consumption? This would help compare if we're dealing with the exact same issue, as different Z3 variants might have slightly different setups. If you've got any other symptoms I haven't mentioned, let me know. Always happy to help a fellow BMW owner!

Hey! Thanks for chiming in! Just had my latest service about 3 weeks ago at 75805 KM, so this issue caught me off guard. You've described almost exactly what I'm experiencing. I did get the codes read at a local shop but wasn't completely sure about their diagnosis. Your experience with the pressure sensor really helps confirm my suspicions. The stalling and power loss have been driving me crazy! Did you notice any warning signs before it completely went bad? Mine started acting up gradually over about two weeks before getting really bad. Would love to know if I can still drive it to the shop or if I should get it towed to avoid any potential damage. Also, that repair cost sounds pretty reasonable, actually. Was worried it might be something much more expensive. Thanks for sharing your experience!

Hey again! Great to hear back from you. Yeah, I remember exactly how mine started acting up, it was also a gradual decline over about 2-3 weeks before it got really bad. Looking back, there were definitely some warning signs I probably should've caught earlier. Started with occasional stumbling at idle, especially when the engine was warm. Then it got worse with unusual power dips while driving. By the third week, that's when the stalling started happening at stop lights, super annoying! About driving it to the shop, I actually drove mine there, but kept the revs moderate and avoided any heavy acceleration. The mechanic later told me it was okay for short distances, but wouldn't recommend doing any long trips. Just take it easy on the throttle if you decide to drive it. And yeah, the repair cost was way better than I expected! Was worried it might be something major like the fuel pump (that would've been a much bigger hit to the wallet). After they replaced the sensor, all those issues disappeared completely. Haven't had a single problem since then. Just make sure they check the wiring connections too when they're in there. Mine had a bit of corrosion on the connector that they cleaned up while doing the job. Probably worth checking on yours too, since our cars are about the same age.

Thanks so much for all the detailed info! That really helps put my mind at ease about driving it to my mechanic tomorrow. Good tip about the wiring connections too, I'll definitely mention that when I take it in. The progression of symptoms you described matches mine perfectly. Started with that annoying stumbling at idle, and now I'm getting those frustrating stalls at stops. Glad to hear yours has been running perfectly since the repair. I'll go ahead and book it in first thing tomorrow morning. Your experience has been super helpful, really appreciate you taking the time to share all the details. Will drive it carefully like you suggested and get this sorted out before it gets any worse. Just crossing my fingers it's as straightforward a fix as yours was. Will probably check back in once it's fixed to let others know how it went. Thanks again for all your help!