possible fuel pump problems, fuel pressure regulator problems, fuel filter plugged, air filter clogged, charcoal canister plugged. There are several issues that need to be checked. The above are places to start
The 2003 GMC Sierra-1500 has a V6 engine.
The 2003 GMC Sierra-2500HD has 16 valves.
The 2003 GMC Sierra-2500HD has a V8 engine.
The 2003 GMC Sierra-1500 has 12 valves.
The 2003 GMC Sierra-1500 is a gas-powered vehicle.
The 2003 GMC Sierra-1500 has a 5-speed manual.
The 2003 GMC Sierra-2500HD has a 5-speed manual.
The 2003 GMC Sierra-2500HD has overhead valves (OHV).
The 2003 GMC Sierra-2500HD is a gas-powered vehicle.
The 2003 GMC Sierra-1500 has overhead valves (OHV).
YES.
The 2003 GMC Sierra-2500HD runs on regular unleaded.