Add the guajillo chilis to a saucepan and cover with water. Bring to a boil and boil them for 5 minutes, then remove from heat. Weigh down the chilis with a coffee mug or plate and let them sit for 10 minutes.
Remove the chilis from the water, destem and deseed the chilis. Add them to a blender or food processor.
Add all the remaining ingredients to the blender, EXCEPT the bay leaves and the pork. Blend until a smooth puree is made.
Pour the chili puree over the meat and turn to coat. I recommend letting the meat marinate for at least an hour or up to overnight.
When ready to cook, transfer the pork and sauce into the instant pot. Place the lid on the instant pot and seal the lid. Choose the meat setting and set the time for 60 minutes.
When the timer is finished, do a rapid release. (Manually release the pressure in the instant pot.)
Remove the meat and place the meat into a large serving dish or bowl. Set the sauce to sauté and cook it, stirring occasionally, until thickened, about 10 minutes. (This step is optional, you can use the sauce directly as is if you are ok with the consistency.)
Using two forks, shred the meat. When the meat is shredded, pour some sauce (or all of the sauce) over the meat. Serve as desired. We like to serve this as tacos with all the toppings!
Notes
Achiote Paste: If you don't want to make homemade, you can buy Achiote Paste at most grocery stories in the ethinic aisle, online, or at a Latin market. Storage: You can store the meat and sauce in an airtight container in the refrigerator for up to 5 days. Freeze for up to 3 months. To reheat any leftovers, simply warm them up in the microwave or on the stovetop.