2001 Lincoln Town Car Running Rich - Check Engine Light On with Fuel Cap Code
I own a 2001 Lincoln Town Car that is running rich in both Bank 1 and Bank 2. The check engine light is currently on, specifically indicating a fuel cap issue. I have already replaced the fuel cap, reset the system, and refilled the tank four times—however, the warning light remains illuminated. Could this be related to an underlying sensor or fuel system problem? I'm seeing a possible fault code related to fuel trim (e.g., P0175), but I'm not certain of the exact diagnostic code. Any guidance on how to properly interpret these codes and perform necessary tests would be greatly appreciated.
Please share the actual fault code you're receiving, such as P0175 or similar. Ensure your OBD2 scanner can read values for ECT (Engine Coolant Temperature), STFT (Short Term Fuel Trim), and LTFT (Long Term Fuel Trim). Also perform a fuel pressure leak-down test to identify any leaking injectors or fuel pressure regulator issues. Regarding the fuel cap—there should be a specific code like P0455 or P0456 if it's causing the issue. Confirming this will help determine whether the problem is truly related to the cap or deeper in the fuel system.