What to Do About Severe Jerking During Buick LaCrosse Acceleration?

[McMaggie]

Here are solutions for severe jerking during Buick LaCrosse acceleration: 1. Adjust Shift RPM: The shifting method involves first increasing the RPM to 2000 before shifting. For some models, the torque output at this RPM may be relatively too high for the power required by the moving vehicle, potentially causing jerking. Therefore, it's necessary to moderately reduce the engine RPM during shifting, such as shifting at 1500 RPM. For large-displacement engines or those with good low-RPM torque, shifting can even be done at low RPMs of 1000-1200 without causing jerking, with minimal impact on acceleration. So, if you frequently experience jerking during shifts, try adjusting (lowering) the engine RPM during shifting to find a level that allows smooth gear engagement without affecting continued acceleration. 2. Adjust the Gear Engagement Sequence to a Progressive Style: Progressive shifting means following the sequence 1-2-3-4-5. In certain situations, using a skip-shift method can also avoid jerking, such as shifting directly from 2nd gear at 2000 RPM to 4th gear, or from 3rd gear to 5th gear. This is based on the principle that the front-end torque output of the powertrain roughly matches the rear-end torque demand, and it is often used more during acceleration on highways or flat roads.

[Gayle]

My Buick LaCrosse has a severe jerking sensation when starting, which is common in automatic transmission models, mainly due to transmission issues. Insufficient or aged transmission fluid can cause rough shifting, so first check the fluid level and color—if it’s dark, replace it with new fluid. Excessive carbon buildup in the throttle body affects air intake and can also cause shaking, which improves significantly after regular cleaning. Worn spark plugs or faulty ignition coils are another cause, and replacing them can help. Faulty sensors, such as the vehicle speed sensor, can lead to incorrect shift timing calculations by the system, requiring an OBD scanner to read trouble codes for resolution. Driving habits also matter—avoid sudden throttle presses, as smooth acceleration reduces impact. Long-term neglect can damage the transmission, so it’s recommended to visit a professional repair shop for inspection and adjustment as soon as possible.