1. Vacuum leak: Check the vacuum lines for cracks or leaks. A vacuum leak can cause the engine to run lean, which can cause it to stumble or stall.
2. Fuel pressure: Check the fuel pressure to make sure it is within the proper range. Low fuel pressure can cause the engine to run lean or stall.
3. Idle air control valve: The idle air control valve regulates the amount of air that flows into the engine at idle. A faulty idle air control valve can cause the engine to stall or idle roughly.
4. O2 sensor: Dirty or faulty O2 sensors can throw off the fuel trims and cause the engine to run lean or fuel rich.
If you are unsure of how to check or repair these components, it is best to take the car to a qualified mechanic.
