why does my BMW 3 Series E90/E91 (2005-2012) shudder when accelerating?

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to ensure safety during repairs.

2. Inspect and Replace Engine Mounts

1. Raise the Vehicle: Use a jack and jack stands to securely lift the vehicle.
2. Remove Undertray: If applicable, remove any undertrays to access the engine mounts.
3. Support the Engine: Use an engine hoist or jack to support the engine from above.
4. Remove Engine Mount Bolts: Unscrew the bolts securing the engine mounts to the engine block and chassis.
5. Replace Mounts: Install new engine mounts and torque the bolts to the manufacturer's specifications (typically around 40 Nm).

3. Inspect Driveshaft and U-joints

1. Visual Inspection: Check for any visible damage or excessive play in the driveshaft and U-joints.
2. Replace U-joints: If damaged, remove the driveshaft, replace the U-joints, and ensure proper alignment when reinstalling.
3. Torque Driveshaft Bolts: Ensure all bolts are tightened to specifications (typically around 25 Nm).

4. Transmission Fluid Check and Replacement

1. Check Fluid Level: Remove the transmission dipstick and check the fluid level.
2. Change Fluid: If fluid is low or dirty, drain the old fluid and replace with the manufacturer-recommended fluid.
3. Replace Filter: If applicable, replace the transmission filter during fluid change.

5. Inspect Ignition Components

1. Remove Ignition Coils: Take off the ignition coils for access to spark plugs.
2. Replace Spark Plugs: If worn, replace spark plugs with new ones, ensuring proper gap settings.
3. Reinstall Coils: Reattach ignition coils and ensure they are seated correctly.