Combine fajita marinade in a gallon freezer bag, mix, add sliced beef, remove air and seal shut. Marinade your thinly sliced beef overnight set into the fridge. (if you want a quicker method you can toss meat with a packet of store bought fajita seasoning packet)
Slice onion and bell peppers, add into pressure cooker with marinated beef.
Squeeze 3 fresh limes into the pot ensuring no seeds land inside.
Mix all ingredients so everything is mixed and/or coated well.
Close lid and steam valve and set to high pressure for 6 minutes. (time will vary depending on thickness of meat pieces and how much meat you are using, this worked well for 2 lbs. cut into med. size strips)
Allow for a natural release for 1 minutes, Then release.
Serve inside small tortillas topped with fresh cilantro, salsa, sour cream, avocado, or any other fajita toppings.