2008 Buick Lucerne Fuel Pressure Code P2030: Diagnosis and Solutions

A fuel pressure drop of 5 psi within 20 minutes is acceptable for a 2008 Buick Lucerne. To troubleshoot, hold the accelerator pedal to the floor during startup to bypass flood mode and observe if engine starts more reliably. A misaligned coolant temperature sensor may cause hard starting when hot, as it could report a falsely low coolant temperature, leading the engine control module (ECM) to inject excessive fuel. When the engine is warm, gently press the gas pedal during startup to see if this improves ignition and combustion. If the vehicle fails to start in 'misfire' or 'no-start no code' mode, it may only respond when the throttle pedal is fully depressed—this behavior suggests a potential issue with fuel delivery or sensor feedback. Ensure proper spark operation when the engine is hot, as weak spark can contribute to starting difficulties. Fuel pressure testing shows consistent readings of 3–5 psi across multiple runs. The pump reaches up to 60 psi, but after turning off the key, pressure drops to 55 psi and holds for nearly exactly 20 minutes before gradually decreasing by about 5 psi every 10 minutes. During this test, a sudden surge in fuel pressure with no throttle response was observed—though no diagnostic codes were recorded. This may indicate an air pocket in the fuel line, especially after opening the Schrader valve on the gauge. The fuel pressure gauge exhibits erratic fluctuations during such events. While the fuel pressure regulator is suspected as a possible cause, the absence of any fault codes and inconsistent symptoms suggest that the issue might not be isolated to the regulator. It may instead point toward an ECM malfunction or a power supply problem affecting the PCM (Powertrain Control Module).