What does the Code 33 mean when troubleshooting a 1988 Ford Truck?

In a 1988 Ford truck, a Code 33 typically indicates a problem with the vehicle's EGR (Exhaust Gas Recirculation) system. This code can suggest that the EGR valve is not functioning properly, possibly due to a blockage, leakage, or electrical issue. It’s important to inspect the EGR valve and related components to ensure they are clean and in good working order, as this can affect the engine's performance and emissions.