Why does the engine speed drop when stepping on the accelerator?

[MollyMarie]

The reasons for the engine speed dropping when stepping on the accelerator are: 1. Use a fuel pressure gauge to measure the fuel system pressure to check if there are any leaks in the fuel system. Slow leaks in the fuel system can cause low cold-start fuel pressure, making it difficult to start; 2. Check if the carbon canister is severely dirty or clogged; 3. Check if there is an issue with the carbon canister solenoid valve. If the solenoid valve remains closed, the gasoline vapor in the carbon canister will accumulate more and more, eventually filling the entire canister, and the remaining gasoline vapor will enter the atmosphere. Conversely, if the solenoid valve remains open, the air-fuel mixture in the engine intake will remain in an enriched state. Since the engine control unit is not yet controlling the solenoid valve at this time, it will not issue a command to reduce fuel injection, which can cause the engine to stall due to an overly rich mixture when the engine is hot. It is recommended that the owner visit a repair shop to use a diagnostic tool to read the engine control system fault codes and analyze the specific fault points based on the codes.