1992 f250 7.3 diesel is hard to start when the engine is cold

. Test glow plugs and GPR, as indicated in the link below:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-8.html#post1415281

. Ensure both batteries are fully charged, cable connections are clean, purge all water and change fuel filter, try adding Amsoil's fuel additive, and be sure to use full-synthetic diesel HDEO with an extended life oil filter.