BMW 4 Diesel Jerking: Throttle Valve or Something Else?

Hi there! I had nearly identical issues with my 2015 BMW 3 Series 320d last year. The symptoms matched yours exactly, jerky acceleration, high fuel consumption, and difficult starts. Initially thought it was the throttle body too, but it turned out to be a defective accelerator pedal module. Had it checked at the dealership where they ran diagnostics and confirmed the faulty module. They showed me the error codes and explained how this component was causing the ECU to receive incorrect pedal position signals, hence the erratic behavior. It was a relatively straightforward fix once properly diagnosed. Took about 2-3 hours for them to replace the module and recalibrate the system. Not a super serious issue, but definitely something that needs fixing as it affects drivability and fuel economy. If you're worried about getting the right diagnosis, I'd suggest going to a BMW specialist or dealership for this one. These symptoms can be tricky to diagnose without proper diagnostic equipment. Hope this helps.

Thanks for sharing your experience! That's really helpful as I'm experiencing the exact same problems. Can you remember roughly how much you ended up paying for the repair? Also, has everything been running smoothly since they fixed it, or have you noticed any other issues pop up? I'm trying to get a sense of whether I should expect any follow-up problems.

Hey again! Yep, happy to fill you in! I actually just checked my invoice, the whole thing cost me 205 € for the accelerator pedal module replacement. And I've got great news, since getting it fixed, my BMW's been running like a dream! The throttle valve problem is completely sorted, and I haven't had a single problem since. The jerky acceleration? Gone. Fuel consumption? Back to normal. Starting issues? Thing purrs to life every single time now. It's honestly such a relief to have it running properly again. I was worried at first that other issues might crop up (you know how these things sometimes go), but it's been smooth sailing for several months now. The mechanic really knew their stuff, just needed that one component replaced and everything fell back into place. Trust me, once you get it sorted, you'll notice the difference straight away. Worth every penny if you ask me! Let me know how you get on with yours!

Thanks so much for all the details! I bit the bullet and took my BMW to a specialist mechanic yesterday. Turns out you were spot on, it was indeed the accelerator pedal module causing all the trouble. The mechanic showed me the diagnostic readings and everything. Got it fixed this morning and honestly, what a difference! The car's running super smooth now, and that annoying jerking is completely gone. Cost me a bit more than yours, 280 €, but it was totally worth it. They even threw in a full system check just to be safe. Can't believe I spent weeks worrying about a major engine problem when it was just this module playing up. Really glad I asked here first, saved me from going down a rabbit hole of unnecessary repairs. Thanks again for pointing me in the right direction. Going to stick with this mechanic too, they really knew their stuff!