What Causes the Peugeot 307 to Shake and Stall During Cold Starts?

[MacAmelia]

Peugeot 307 shaking and stalling during cold starts is caused by excessive carbon buildup. The details are as follows: 1. Excessive carbon deposits on the inner wall of the throttle body can lead to insufficient air intake, making it difficult to start or causing the engine to stall easily at idle. Once the coolant reaches the engine's normal operating temperature, the throttle opening may exceed the normal idle value, causing the ECU to repeatedly adjust the throttle valve plate position, resulting in fluctuating idle speeds. 2. In non-direct injection engines, gasoline is injected into the intake space near the intake valve head. Impurities, wax, and unburned carbon compounds accumulate in this area. The carbon deposits have a loose, sponge-like surface. After sitting overnight or for an extended period, during a cold start, most of the fuel injected by the injectors is initially absorbed by these deposits. This leads to insufficient fuel entering the combustion chamber, creating a lean mixture and making ignition difficult.