BMW X3 Diesel: Jerking and Stalling, Intake Manifold Issue?

Hey there! I can relate as I had a pretty similar issue with my 2001 BMW X5 diesel last year. I have some experience working on cars, mainly basic maintenance and troubleshooting. Your symptoms sound exactly like what I went through, the rough idle, jerking, and that annoying limp mode. My workshop found that the intake manifold was scorched and leaking badly. They had to replace the entire manifold assembly, and while it wasn't cheap (cost me around 1180 Euro), it fixed the problem completely. The repair took about a day and a half at my trusted mechanic's. They also recommended cleaning the EGR valve while they were at it, which made sense since they had to remove it anyway. Could you share some more details about your X3? Like the mileage and service history? Also, have you noticed any other warning lights or unusual sounds? This would help determine if you're dealing with the same issue I had.

Thanks for sharing your experience! My X3 has 82227 KM on the clock and just had its service last month. The symptoms you described with your X5 sound spot-on with what I'm experiencing. I'm getting a bit worried about the repair costs, but it's good to know what to expect. The only other thing I've noticed is a slight whistling noise when accelerating, which wasn't there before. No additional warning lights besides the check engine light though. Did you notice any similar sounds with yours before the repair? Looking at the repair cost you mentioned, I might need to start saving up. Really helpful to know it took about a day and a half, helps me plan for the downtime. Did you find any temporary fixes while you were waiting to get it repaired?

Hey again! Yeah, that whistling noise you mentioned, I definitely had that too with my X5! It's actually a pretty classic symptom of a failing intake manifold. Mine started with just a faint whistle, but it got more noticeable over time. I tried a few temporary fixes while saving up for the repair, but honestly, none of them really solved the problem. I found that driving more gently and avoiding hard acceleration helped reduce the jerking a bit. Also tried cleaning the mass airflow sensor myself, which seemed to help with the idle for a short while, but the problems came right back. With your mileage being similar to what mine was when it failed, it's probably the same issue. Just be careful not to wait too long, I learned the hard way that driving with these symptoms can potentially cause more damage. The exhaust smell you mentioned is particularly concerning, as it was in my case too. One thing I forgot to mention in my first reply, after the repair, my fuel economy improved quite a bit. Guess the faulty manifold was causing the engine to run rich. The whistling disappeared completely too. Let me know how it goes if you get it checked out. Always good to compare notes on these things, especially with these older BMWs!

Thanks for all that additional info! That's really reassuring to know you had the exact same whistling sound. I'm definitely going to take it in sooner rather than later, don't want to risk causing more damage like you mentioned. Good tip about driving gently in the meantime, I'll try that and maybe clean the mass airflow sensor too while I save up for the repair. Interesting about the fuel economy improvement after fixing it. Mine has been pretty terrible lately, so that would be a nice bonus after getting it repaired. Think I'll book it in next week at my regular workshop. They've worked on BMWs before, so hopefully they can sort it out just as well as your mechanic did. Really appreciate you taking the time to share your experience, it's been super helpful knowing what to expect. I'll probably avoid any long trips until it's fixed. Will let you know how it goes after the repair! Thanks again for all your advice!