Hello,
It is very kind of you to care for this little foundling, and I am sorry she is having trouble. Pedialyte is not a sufficient diet for this kitten, so you should start the KMR again ASAP. KMR is specifically formulated for kittens that do not have the benefit of nursing from their mother, and contains many thngs (colostrum, for one) that developing kittens need. The diarrhea is very concerning, because she is so young and small, and cannot afford to lose so much fluid. I worry that the diarrhea may be due to a combination of things, like stress, diet change (which cannot be helped since you just found this baby) and intestinal parasites. Parasites are very common in kittens and can reach life threatening severity very quickly in the young. If you want to ensure this kittens best chances for survival, you will need to have her seen by a vet ASAP. She should be seen tonight, and really cannot wait until the morning, especially if she is still having severe diarrhea. The longer you wait to have her seen, the more difficult and expensive it will be to make her better. Having her seen by an emergency vet this evening as opposed to waiting until tomorrow may save you the expense of hospitalization and iv fluids, and will save her the discomfort. Please try to have her seen right away and let me know if I can be of further assistance. If this has been helpful, please hit the green accept button. Best of luck with your baby kitty :)
Emergency Critical Care Nurse
16+ years of veterinary experience