Since the first release of the season four DVD set had syndicated episodes on it, it's easy to tell what scenes were edited out for syndication. So far I noticed:

Surely You Joust- While Estelle, Harriette, and Rachel are folding laundry, Laura comes in and is grossed out by some lingerie she found. Harriette thinks its Rachel's but Rachel say its not hers. They then realize it's Estelle's. Laura asks why she would buy that, Estelle tells her she didn't, it was a gift. Also when Waldo's yelling up the chimney about the TV I don't think they showed Rachel mumble to Harriette, "That's a stupid boy," before.

Dance to the Music- At the dance I think they had edited out the principal talking about the football team losing.

Rumor Has it- During the cold open Waldo asks Steve to sign a petition to get a new mascot because he killed the other one. Another is Rachel, Estelle, and Laura walk in and tell Carl and Harriette they're helping Laura pick an outfit for her date with Ted. Harriette tells Rachel she doesn't want Laura dressing like her. Mother Winslow says that she'll be there to advise as well, and Carl and Harriette say "Oh Lord".

Number One with a Bullet (still edited out)- Richie gives Steve a magazine to feel better. Steve thanks him. Judy interjects that it's from both of them. Richie says, "But I found it in the dumpster!" Judy says, "Yeah, but I held your feet!" Which all grosses out Steve.

Whose Kid Is it Anyway?- During the cold open Steve says he would have entered a pumpkin in the family contest but a 5 year old girl took his from him. Later, Steve tells Harriette while his father had insomnia he wrote three operas and carved a family out of walnuts. Also Eddie answering the door and scaring the trick or treaters with a spider.

An Officer and a Waldo- I don't think Richie eating the melting popsicles while Carl fixes the freezer was on the syndicated ep. Also when Waldo writes a letter to his mother and it ends up rhyming like a limerick.

Feel free to add to the list, I will too as I continue watching the episodes.

Just One Date- At the end of the cold open when Steve realizes Laura left and he's singing to Carl, Carl says, "Hey. The Earth didn't move for me either, OK?" After Urkel tells Laura hes going to ask her out for the thousandth time, she says "You actually keep track?" to which Urkel says yes, and he used to tally it up on his bed but ran out of kindling. They also cut out Richie tell Gwendolyn her cupcake is lopsided but he likes the color blue.

The Oddest Couple- They cut out Weasel introducing himself to Carl. Also at the start of the tag scene they cut out Eddie at home eating and Harriette wondering where Laura is.

Its A Mad Mad Madhouse- They cut out Waldo asking Miss Connors what the thing in the back of your throat is called. She asks what that has to do with math, but tells him its the uvula. Also they cut out her saying that you may be intimated by the logs at first but not to be when there's a poster of a model in a bikini over the logs. Also Carl and Harriette continuing to argue as they go upstairs while the doorbell rings. Richie and Judy run over and Richie shoves Judy and says he'll get it. Judy says, "Why? It's probably for me, you don't have any friends!"

Its Beginning to Look Alot Like Urkel- At the end of the cold open when Steve gets snow on everyone with his invention, Richie tells Steve to do it again. They also cut out Carl having to drag Harriette away as she tries to fight with Laura Urkel.