Cylinder numbers for 2003 ford 3.0 flex fuel?

The 2003 Ford 3.0L Vulcan V6 engine (flex-fuel or not) uses a firing order of 1-5-3-6-2-4. However, this doesn't directly translate to cylinder *numbers* on the engine block as there's no standard numbering system universally used across all engine manufacturers. You'll need to consult a repair manual specific to your 2003 Ford 3.0L engine to determine the physical cylinder numbering. The firing order is more relevant for troubleshooting ignition and fuel delivery problems.