A member of BMW's illustrious 3 Series, the BMW 330i is one of the most remarkable models to come out of the line. While it didn't debut during the series' earlier generations, the 330i has already had several versions throughout the years. Each version of course improved from previous installments. However, with each new version also came new difficulties. Below are some of the most common problems encountered when driving a 330i.
Several suspension components of the E46 BMW 330i (which was released in 1999) were reported to be weak. The said parts, which included rear coil springs and ball joints, usually wouldn't last that long before they would break. There were also a few reports of the rear suspension mount surprisingly breaking through the car floor, as well as faulty front control arms and rotors that caused vibrations.
The E46 BMW 330i came with a then-new M54 engine. While the said engine was generally both heavy-duty and reliable, there were still problems that arose (mostly limited to models with manual gearboxes and those that have the unique high-performance ZHP package). This included reports of the M54 engine's ECUs (electronic control units) being plagued by rough idles, power delivery issues, and flat spotting. Because of those, the M54's ECUs needed to be overhauled.
Although BMW fixed those issues in the next generation (E90) of the 330i, there were still some reports of automatic gearboxes that experience difficulty in shifting.
Steering also became an issue for some E46 BMW 330is as there were several reports of owners experiencing heavy steering. BMW addressed this problem by retrofitting the 330is of the complaining owners with new steering racks. With the improved steering capabilities of the then-problematic 330is, the issue was eventually put to rest.
Although this is a minor issue, the E46 BMW 330i's sunroof problems bugged some owners. For instance, the sunroof often got stuck. Owners were advised to regularly grease the sunroof tracks to prevent that from happening. Another complaint regarding the sunroof was that it tended to forget its initialization for various positions. BMW released instructions on how to fix it though.