BMW Z3 Throttle Valve Issues: Symptoms & Solutions?

Hey there! I have some experience working on cars, and this sounds very familiar. I had a similar issue with my '03 BMW M3 last year (my second BMW after owning a 325i). The symptoms you're describing match exactly what I experienced, sluggish acceleration, poor throttle response, and higher fuel consumption. Turned out to be a faulty accelerator pedal module. My mechanic diagnosed it, replaced the module, and it ran like new again. The whole thing cost me 205 Euro, but it was worth every penny because all those issues disappeared. Before recommending anything specific though, could you tell us: Any warning lights on the dash? Does it happen more when the engine is cold or warm? Have you noticed any odd noises when pressing the accelerator? This info would help confirm if you're dealing with the same problem I had.

Thanks for the detailed reply! Just had my service done last month at 58515 KM. No warning lights at all on the dash, but the jerking happens pretty much all the time, especially right after I press the gas pedal. It's like there's a delay before the car actually responds. There's also this weird small clicking sound when I press the accelerator, not super loud but definitely noticeable. The engine temp doesn't seem to make much difference, it acts up whether cold or warm. I was thinking throttle valve, but your accelerator pedal module suggestion is interesting. Maybe I'll have my mechanic check both. The symptoms sound pretty similar to what you experienced.

Hey again! Yeah, that clicking sound you mentioned with the accelerator, that's exactly what I heard in my M3 before I got it fixed. It's actually a really common thing with these models. When you described the delay in response, it took me right back to my experience. I remember being so frustrated with that lag between pressing the pedal and the actual acceleration. At first, I was convinced it was the throttle valve too, but the clicking sound was the giveaway. The accelerator pedal module acts up in such a specific way, it's almost like a signature problem for these BMWs. Since you mentioned getting serviced recently at 58k, it's probably not a maintenance issue. My M3 was around 62k when I had the same problem. The symptoms are spot on, same jerking, same delay, same fuel consumption issues. Getting both checked is smart, but I'd put money on the accelerator pedal module being the culprit. Quick tip though, when my mechanic replaced mine, he mentioned getting a genuine BMW part rather than aftermarket. The aftermarket ones tend to act up again after a few months. Learned that lesson with my previous 325i! Let me know what your mechanic finds. I'm really curious if it turns out to be the same issue!

Thanks so much for sharing your experience! That's super helpful, especially the tip about getting the genuine BMW part. I was actually considering going aftermarket to save some money, but definitely not worth it if it's just going to fail again in a few months. The more you describe your situation, the more convinced I am that we're dealing with the same problem. I'm calling my mechanic first thing tomorrow to get it checked out. Will definitely focus on the accelerator pedal module first, seems like the most logical place to start given all the similarities with your M3's symptoms. That clicking sound being a telltale sign really sealed it for me. I'll make sure to insist on OEM parts too. Had enough headaches with this issue already, don't need it coming back in a few months! Thanks again for all the detailed info, really saved me from potentially going down the wrong path with the throttle valve. I'll update once I get it sorted out!