I've tried cleaning the print heads and replacing the red ink cartridge, but the red color is still weak. What else could be wrong?

If print head cleaning and a new red ink cartridge haven't resolved the issue, the problem might be more complex. Potential causes include a malfunctioning color wheel, an issue with the printer's firmware, or a problem with the ink delivery system. Contact Epson support or a qualified printer technician for further diagnosis and repair. A color wheel issue is often difficult to self-diagnose and repair.