The Hole-in-the-Wall Gang - S4-E21
Plot hole: When Stephanie and DJ start singing that dad song in their room, Michelle come in and starts singing. After she goes, DJ and Stephanie have a talk. After two minutes, Michelle comes in, dressed like they are. How could a 4-year-old girl change to teenage clothes and fix her hair in two minutes? Danny was in his room (because he found the baking soda), and Jesse and Joey were too busy with Jesse and Becky's room to help her change.
Suggested correction: However it could have been Kimmy as she was seen in the tanner house hold not that earlier in that episode and may have never left.
Radio Days - S6-E4
Plot hole: At the end of Joey and Jesse's radio interview, the host Julie says "Joey Gladstone." However this appears to be the first time she's met him and when Jesse introduced him to her a few minutes before (in real time), he referred to him only as "Joey" and never once told her his surname nor is it mentioned in the interview. Furthermore, she also said she wasn't aware of The Ranger Joe Show so it doesn't make sense for her to suddenly know his last name minutes later when she was never told it previously.
You Pet It, You Bought It - S8-E6
Plot hole: When Jesse and Michelle wake up in the morning, you can see that the picture Danny got was behind the couch, resting on the seat in the alcove. Later, when Danny goes into the living room and screams, Shorty is standing in the middle of the room, with his head in the picture, and the picture is facing the family. There is no way that the donkey could have put his head in that way.
Claire and Present Danger - S8-E8
Plot hole: When Danny tells Michelle to change out of her punk get-up, Michelle does, and she comes back shortly after with her hair arranged perfectly in a nice half ponytail. However, in her previous scene, she had used hairspray to make her hair all frizzy and going every which way, so it's physically impossible that she got it to be completely straight and clean again, unless she went home and washed it.