Why does the new LaCrosse experience low-speed jerking?
3 Answers
The low-speed jerking in the new LaCrosse is caused by engine oil passage blockage. Solutions for engine oil passage blockage: Directly add fuel cleaner to the fuel tank. This is the simplest method, but the effect is not long-lasting, and the cleaning is not thorough. It is suitable for vehicles with shorter mileage. You can also clean the carbon deposits and deposits in the fuel system and intake valves simultaneously, or completely remove the entire fuel system for thorough cleaning. Solutions for low-speed jerking in cars: If the throttle is slightly larger, and both the engine speed and vehicle speed are significantly higher than the shifting standard, the jerking sensation during shifting will be relatively minor. The jerking sensation is caused by a mismatch between the engine and vehicle speed. Before shifting while driving, consciously release the throttle slightly, and the transmission will respond immediately.
I just picked up my new LaCrosse last month and noticed the low-speed jerkiness issue right from the start, especially noticeable between 20-40 km/h when the car feels like it's surging. After researching and consulting experienced drivers, I found that GM's 9AT transmission has an aggressive low-speed lock-up strategy where the torque converter engages prematurely. The shift logic also tends to hesitate during stop-and-go traffic. Additionally, the electronic throttle response is somewhat sluggish, with noticeable non-linearity in slight throttle inputs. The jerkiness is most pronounced during the first few minutes after a cold start, improving slightly once the transmission fluid warms up. The issue can also worsen after refueling or prolonged low-RPM driving when the transmission's adaptive learning values haven't properly adjusted. Fortunately, this isn't a major defect - it usually improves after some driving as the computer adapts or through software updates.
Having been used to driving Japanese cars before, the most uncomfortable part of switching to the new LaCrosse is the low-speed jerkiness. Every time I'm in traffic, following other cars is particularly agonizing. When you release the throttle at around 30 km/h and then lightly press it again, you can clearly feel a gap in power delivery, as if being gently tugged. The mechanic said it's mainly because the transmission doesn't downshift and rev-match quickly enough, combined with the turbocharger not kicking in at low RPMs, leading to some torque fluctuations. Later, I learned a trick: using Sport mode at low speeds to delay upshifting makes it much smoother, or avoiding abrupt throttle inputs. Actually, many turbocharged cars from German and American brands have similar issues—it mostly depends on how well the manufacturer tunes it. Recently, I saw someone on the forum mention that after updating the TCU program at the dealership, the jerkiness was significantly reduced.
