Ford Explorer shudders during acceleration at 40 and 60 mph, issue persists after spark plug replacement on Ford Explorer

Some Ford Explorer owners report experiencing shuddering during acceleration at speeds between 40 and 60 mph, even after replacing the spark plugs. This issue may be linked to transmission problems, such as a failing torque converter or issues with the transmission fluid. Additionally, some owners note that vibrations at higher speeds could indicate wheel and tire issues, including imbalance or misalignment. Others have found that a faulty harmonic balancer may be responsible for the symptoms, particularly during uphill driving. Furthermore, shuddering that occurs after the vehicle has been run to temperature and then parked could be related to temperature-sensitive components like sensors or the fuel system. Given the persistence of these issues, further investigation is recommended to effectively address the underlying problems.