Experiencing performance issues with your Mercedes Benz C240 can be frustrating, especially when trying to diagnose the root cause. One owner of a 2005 Mercedes Benz C240 is facing a range of symptoms, including engine sputtering, inconsistent acceleration, and concerns about the automatic transmission. Having purchased the car with only 5,000 miles in 2005, and adding 60,000 miles over the next six years, the car has been a reliable companion, albeit with some prior maintenance.
Recently, however, a series of problems have emerged that are causing concern. When coming to a complete stop, the engine exhibits a noticeable sputter, almost as if it’s about to stall. This issue is temporarily resolved by shifting the car into neutral and briefly pumping the gas pedal. Returning to drive mode usually alleviates the sputtering, at least for a short period.
Another intermittent problem occurs when attempting to accelerate from a standstill. In these instances, pressing the gas pedal yields no response. The car fails to accelerate, and the RPMs remain unchanged. Releasing the gas and pumping it again is sometimes required to restore normal acceleration.
Furthermore, there are instances of delayed gear shifting accompanied by high RPMs. When accelerating from a stop, the engine RPMs climb excessively and remain elevated, indicating a delay in the automatic transmission shifting to the next gear. This can be managed by modulating the gas pedal – applying and releasing pressure, mimicking manual gear shifting – to encourage smoother gear transitions.
The vehicle is equipped with an automatic transmission that includes a sport shifter feature. The owner has raised concern about potential unintended consequences of using the sport shifter, specifically recalling instances of accidentally stopping the car in 4th, 3rd, or 2nd gear before realizing and reverting back to automatic mode.
Given these symptoms, the primary questions are whether these performance issues are indicative of a transmission problem, or if they point to another underlying fault. The owner is contemplating the best course of action: is the car inherently problematic (“a lemon”)? Should they consider replacing the vehicle to avoid further repair costs and potential car payments, or is it more prudent to invest in diagnosing and repairing the existing Mercedes Benz C240, considering the prior investment and current outright ownership?
Following an initial assessment at a transmission shop, a surprising diagnosis was offered. The mechanics suggested that the issues might not be transmission-related at all, but rather stem from a problem within the exhaust system. To investigate this further, the owner planned to seek a second opinion from a different mechanic specializing in exhaust systems.
The transmission shop also noted that the transmission unit is indeed a Mercedes-Benz original part, identifiable by specific manufacturer markings and numbers. This raises uncertainty about the car’s service history: it remains unclear whether the transmission was previously fully replaced or simply repaired during prior maintenance, as records are incomplete. The mechanic who performed the previous transmission work is no longer available to provide clarification.
