BMW Z3 DISA Valve Problems Causing Multiple Engine Issues

Hey there! I have some experience working on BMWs. Had a similar issue with my 2002 BMW 3 Series (325i). The symptoms you're describing sound exactly like what I went through, the power loss and rough idle were super annoying. Took it to my trusted workshop and they diagnosed a faulty DISA valve. The entire unit needed replacement, couldn't just fix parts of it. Total repair cost me about 280 Euro, but it was totally worth it. Car ran like new afterward. Quick question though, have you had the diagnostic codes read? Also, can you share your engine type? This would help me give you more specific advice since DISA issues can vary between different BMW engines. If you're getting these symptoms, don't wait too long to get it checked. Mine got worse pretty quickly and started affecting overall engine performance.

Thanks for sharing your experience! Mine's at 96308 KM and just had the service done last month. Got the diagnostic codes read yesterday, they're pointing towards intake system issues. The power loss is really bugging me, especially when trying to overtake. Glad to hear replacing the DISA valve fixed it for you. Might take mine to the shop this week then, rather than waiting for it to get worse. The repair cost seems reasonable if it sorts out all these annoying symptoms.

Hey again! Just wanted to follow up on this since I've been through the exact same ordeal with my 325i. After I replaced my DISA valve, I actually kept a close eye on the symptoms to make sure everything was sorted properly. The repair totally fixed all those issues you mentioned, the power loss, rough idle, everything. I've put on about 30000 KM since the repair and haven't had a single problem related to it. It's running smooth as butter now. One thing I learned though, it's worth having them check the intake boot and vacuum lines while they're in there. My mechanic spotted a small crack in one of the vacuum lines during the DISA replacement. Got that fixed at the same time, which probably helped with the overall improvement. The diagnostic codes pointing to intake issues definitely back up the DISA valve theory. Mine showed similar codes. Honestly, getting it fixed sooner rather than later was one of the best decisions I made. The car's performance difference was like night and day. Keep us posted on how the repair goes! Always good to hear feedback on these fixes, especially with these BMWs that seem to share so many common issues.

Thanks so much for the detailed follow-up! Just got back from booking my Z3 into the workshop for tomorrow morning. They're going to do a full inspection of the intake system while replacing the DISA valve. Really appreciate the tip about checking the vacuum lines too, I've mentioned that to them specifically. It's honestly such a relief hearing that the repair completely solved your issues. My car's been my pride and joy since I got it, and these problems have been really frustrating. Can't wait to get that smooth performance back, especially since I use this car daily. The workshop quoted me slightly higher than what you paid, around 350 Euro including labor, but I'd rather get it done properly than risk more issues down the line. I'll definitely update the thread once everything's fixed, might help other BMW owners facing similar problems. Thanks again for all your help with this!