20 15 Mercedes-Benz e260l engine compartment jitter, what is the problem, 4s said all new models are like this! I don't know if it's true or not

Causes of engine jitter: using inferior engine oil and gasoline, there are many impurities in fuel and serious carbon deposition. Either poor engine lubrication or poor cooling will lead to engine jitter. If low-grade gasoline is used, it may cause deflagration due to insufficient antiknock performance. Then there is:

Long-term low-speed driving causes carbon deposition on valves and throttles.