Although the AC/DC concert was set in 1985, Phil Rudd was not yet a member of the band at that time, although he is shown in the scene. IN addition, he can be seen playing using Ahead-brand aluminum drumsticks. These sticks were not introduced until the mid-'90s.
When Howard is backstage at the 1992 MTV Music Awards, John Popper of Blues Traveler is seen playing his harmonica in the background. Although the band formed in 1987, Blues Traveler was virtually unknown until their breakout album "Four", which was released in 1994. Popper would certainly not have been backstage at the 1992 MTV Music Awards.
The bass player in AC/DC is playing an Ernie Ball Music Man Sting Ray 20th Anniversary Special Edition Bass. The scene is set in the mid-'80s, but the bass he is playing wasn't introduced until the late 1990s.
As Howard's car is seen driving over a bridge, on his way to New York for his new job at WNBC, David Bowie's "Let's Dance" is playing. Howard's first official day at WNBC was September 6, 1982, so obviously he had to arrive in New York around that date. However, "Let's Dance" was not released until March 17, 1983.
When Howard and Allison are driving from Detroit to Washington, D.C., Howard gets out of the car to fill the gas tank. The delivery hose on the gasoline dispenser had been modernized with a "Stage II Vapor Recovery" system, which was not introduced until the late-'80s.
When Howard and Robin walk out of NBC headquarters in New York after she was fired, you can see the current NBC peacock logo in the entry way to NBC's headquarters in the background. The scene takes place in 1981-82, when NBC's "Proud N" logo would have been in use. The current peacock was introduced in the spring of 1986.
When Howard arrives at WCCC, he is standing at the studio door as Fred finishes his program. To the left of the door, there is an "on air" light that is initially off, even though Fred is broadcasting. In the next shot, when Howard enters the studio, the "on air" light is on, and is then turned off.
Alison announced her (successful) pregnancy at the same time Howard announced his move to WNBC in New York, which was in 1982. Alison's water broke at the ACDC rally in midtown NYC in 1985. That means Alison is shown to have a 3 year pregnancy! In reality, Howard's oldest of 3 daughters was about 2 when he was fired from WNBC in October 1985.
While Howard is in Washington DC, he helps a woman have an orgasm over the air. When this happens, the scene shows a car with New York plates jump the curb at an intersection along E 189th St in the Bronx. The radio station in Washington DC was local and not syndicated so somebody in New York couldn't be listening.
Howard is attempting to give a woman an orgasm over the phone. He is speaking to her on the phone and at the same time she is listening to the show on the radio. There is a time delay of several seconds before the show is broadcast over the air. Being on the phone and listening at the same time would create feedback and would not allow the conversation to continue as portrayed.
Robin makes the statement that Howard, "...wasn't old enough to be in Vietnam" and Howard replies, "no duh". The Vietnam War started in 1965 and ended in 1975. Howard was 18 years of age in 1972 which does make him old enough to be in the war.
When Howard and Allison pull into the gas station and he discusses the fact that he often holds back what he is really thinking while on the air, you can clearly see the car's rear-view mirror folded upwards and out of the way in order to avoid blocking the faces during the conversation.
The goof item below may give away important plot points.
Errors in geography
During Pig Vomit's rant at the end of the film, he says he manages a mall in Florence, Alabama, claiming it's the "number one mall in Colbert County". The town of Florence is located in adjacent Lauderdale County.