Factual error: In the scene of Jimmy driving with his new Mercedes, we can see a Subaru forester that is definitely a model after 2010. Season 2 is set in 2002 so this couldn't be possible.
Continuity mistake: Hector goes behind the counter in Los Pollos Hermanos and helps himself to a drink. The cup is under a different dispenser (and therefore a different drink) each time the shot changes, but the audio of the dispensing and the cup being filled remains intact throughout.
Continuity mistake: In the scene after Jimmy/Saul and Mike in the desert with the seven mil, they are each sitting on one of the duffel bags of money at the gas station. Mike puts his big drink up to his head and his watch reads 6:35 but in the next shot it reads 3:00.
Sunk Costs - S3-E3
Other mistake: While setting up the shot to drop drugs on the Salamanca truck, Mike puts the drugs in the left sneaker. He later shoots through the right sneaker. (00:29:29 - 00:38:06)
Factual error: Tuco Salamanca's gun is a Taurus Raging Judge. Season 1 - as well as Season 2 - where Tuco's gun is prominently featured, are set in 2002. The Taurus Judge series wasn't produced until 2006.
Factual error: In one of the shots shown of Chicago, the Trump Tower can be seen on the right. Although the episode is set in 2002, this building did not exist until the late 2000s. (00:28:33)
Continuity mistake: Jimmy gets ambushed. One gang member holds a gun close to Jimmy's face, but in the next shot the guy is way further away from him and not even visible in the shot when Jimmy gets splattered with blood.
Visible crew/equipment: At the end of the episode you as Jimmy is sat on the floor, you can see the head of a camera man or sound technician duck down to the left of Jimmy.
Factual error: When Hector and his men are in Los Pollos Hermanos there's a soda machine in the background with the current logos of the sodas when this episode took place before 2003. (00:12:33)
Continuity mistake: The sky changes multiple times during the opening sequence. It goes from clear and sunny to much cloudier depending on the angle.
Continuity mistake: Jimmy shows up at Irene's door with a box and some balloons. From the side view as she opens the door, the balloon with flowers on it is closest to the door with the pink and blue peppermint swirl balloon behind it. When the camera cuts to looking at Jimmy from inside over Irene's shoulder, the peppermint balloon is now in front with the flower balloon up higher between it and the other balloon. (00:28:36)
Continuity mistake: Near the beginning when they are staging the crime scene, the car with the flat tires moves between being on the road and further off to the side during the angle changes.
Continuity mistake: While Kim is talking to Jimmy he is pulling of the tape off the wall. As she sits down to the couch, Jimmy's hands are at the same height as his head. After a cut, his hands on the wall are suddenly at a much higher level. About 50cm of pulling off the tape on the wall are being skipped. (00:40:37)
Continuity mistake: When Jimmy and the kids pull into the news station, the shadows of the dishes and tower drastically change positions from when the park to when they get out of the car.
Continuity mistake: The newspaper Hector is reading when Domingo comes in keeps changing around. For example, when you see him reading the sports page, there's half a picture of a baseball player on the front and the bottom half should be seen on the side Hector is reading. When we see what he's reading, part of the picture is now a football player.
Gloves Off - S2-E4
Continuity mistake: Tuco is confronting Mike out in the parking lot. When Mike offers to exchange information he's standing slightly to the left of Tuco as he faces him, with his head turned to Mike's left looking at him. But each time the camera cuts to a side view of them both, Tuco is closer to standing right in front of Mike, with Mike's head turned slightly to his right.
Continuity mistake: Once Jimmy realises Chuck is about to enter the room, he reaches for his glass and holds it up to his face for a drink. In this shot, Kim is looking down at the table. The camera changes angles as he's taking a sip, and suddenly Kim is looking to the side at him.