Continuity mistake: Just before Cheech gets up from the couch, a girl is getting up from the floor. When Cheech is putting his foot into the bowl of cereal, you can see the girl's knee as she is still sitting on the floor. (00:00:40)
Continuity mistake: When Chong is on the phone with Cheech and about to go outside you can see a man in a white hat dancing by himself. When it cuts the same man is dancing with a woman. (00:31:00)
Continuity mistake: When Cheech picks up Chong in his car, Chong has some grass in his beard. The grass changes position between the shots. (00:08:20)
Visible crew/equipment: When Cheech and Chong get to the border, Cheech spots some nuns in the car beside them. Watch closely in the window of the van when Cheech is looking at the nuns. You can see a man standing there looking at something and then looking at the van. This man wasn't standing there when there was a wide shot of the scenery. (00:44:45)
Continuity mistake: When Chong is trying to calm Cheech down in the car, Cheech is sitting with both hands up. When it cuts, his hands are down. (00:15:15)
Continuity mistake: When Cheech and Chong get to the courtroom, there are two pencils on their table. When Chong falls to the floor, no pencils are to be seen. (00:18:35)
Continuity mistake: When Cheech tells the cop that his name is Pedro de Pacas, Cheech is holding his wallet. When it cuts, the wallet is gone and he is holding the wheel instead. (00:17:05)
Continuity mistake: When Curtis is talking to Cheech about his car and says "you got a taste of soul", Cheech is standing with both his hands in his pockets. When it cuts, Cheech suddenly has a hand scratching his chin. (00:34:25)
Continuity mistake: Cheech picks up Chong hitch-hiking by the parking lot at Zuma beach in Malibu. They drive south, with the ocean always to their right. Approximately 2.5 minutes later, they pass the same distinctive location again, still driving south. (00:08:20 - 00:10:55)
Continuity mistake: The drum kit is a Ludwig amber Vistalite (see Keith Moon, who had a clear one, and Karen Carpenter, a blue one, neither had bottom heads) like John Bonham played in the Song Remains the same. The drum head on the kick drum in the back seat is on and off in the same scene repeatedly. They're a pain to remove, so it's physically impossible to do so and replace in the same conversation.
Continuity mistake: Right before the car crashes into the police car that has stopped behind Cheech, you see a red car pass the police car. When it cuts, the red car passes the police car again. (00:09:00)
Continuity mistake: Cheech picks up Chong and they sit in the car and talk. When Chong says "Wow, looks fantastic," Cheech is looking at him, but when it cuts Cheech is looking in the mirror fixing his cap. (00:08:20)
Continuity mistake: The kid turns on their television. It cuts and all the kids are far away from the TV. The one that turned it on couldn't have moved away from it that fast. (00:00:20)
Continuity mistake: Right after Cheech puts his foot in the bowl of cereal, he's lying down backwards on the couch and tipping his head back. When it cuts, he suddenly is getting up from the couch. (00:00:50)
Continuity mistake: When Cheech sings "Keep on knocking but you can't come in" to the cop, you see the cop pointing at the car window. When it cuts the cop isn't pointing anymore. (00:16:15)
Answer: The lead singer is Rick Wilder. The band is credited as "Berlin Brats" (The Groups). The song is called "Psychotic", or sometimes listed as " (I'm) Psychotic", but it seems the middle part was cut out for the film or maybe arranged differently for the film.
Bishop73