Revealing mistake: When Arnie drives through the police station, the cop is just sitting there. Not only that, his skin is a lot paler. It is too easy to see that it is a dummy. (01:00:00)
Revealing mistake: When the Terminator goes in to the Alamo gun store, scene of the famous "Uzi 9 millimeter" quote, the man turns to get something off the shelf and Arnold takes a shell out of the box on the counter. It is an already fired cartridge: the dimple in the centre shows it.
Revealing mistake: During the final chase scene, Sarah loses control of the pickup and it rolls over, as it rolls you can plainly see that it has no engine. (01:26:05)
Visible crew/equipment: As the Terminator moves his right arm whilst in the press, you can see a crew member, behind the Terminator, move in the area of the picture where its arm was. (01:34:05)
Continuity mistake: Kyle loads a shell into his shotgun then falls asleep and dreams of his past in the future. When he wakes up he pumps the shotgun, so the first shell should come out, but doesn't. (00:20:05)
Continuity mistake: When Ginger is rooting through the fridge while her boyfriend fends off The Terminator in the bedroom, Pugsley the iguana scares her by knocking some food off the top of the fridge. We then see a close up shot of Pugsley knocking some more food over. In this shot we see him knock over a box of "Harvest Wheats" onto its front and a box of "Honey Grahams" placed on its side and at an angle. We then cut back to Ginger telling him to shoo and then back to Pugsley. In this second shot, the box of "Honey Grahams" is now standing upright and facing the camera and the box of "Harvest Wheats" has completely disappeared. (00:30:40)
Continuity mistake: When the tanker explodes near the end, the Terminator gets out of the truck on the left-hand side of the cab, and falls to the ground. When the endoskeleton arises minutes later, however, it is on the opposite side of the cab (Sarah approaches Reese from the right side, and the endoskeleton arises in the background). (01:29:25)
Factual error: In the scene after Arnold says "I'll be back", it shows the desk cop writing a report with a pencil. Any public servant or corporation knows, reports are only written with BLUE or BLACK INK... NEVER with a pencil. (00:59:15)
Continuity mistake: When the tanker explodes near the end, the Terminator gets out of the truck, then falls to the ground face-first, in an open area. Then he rolls over onto his back, lying prone, and stops moving. When the endoskeleton rises a minute or so later, however, it gets up as if it had been hunched over, face down - and several pieces of the truck's wreckage fall off of it as it rises, as if it had been covered by falling metal. (01:28:45 - 01:31:00)
Continuity mistake: After Kyle saves Sara from the dance club and has her in the car she tries to get out. Kyle stops her by grabbing her. In one scene he's holding her by the back of her hair, and when it cuts back to him his hand is across her chest. It goes back and forth like that. (00:37:20)
Factual error: Sarah and Lieutenant Traxler both state that Tech Noir, the club Sarah is in, is on Pico Boulevard. After the gun battle inside the club, Sarah leaves with Kyle and they run a short distance down the alley behind the club before getting into a car. The Terminator jumps on and falls off as soon as the car is out of the alley. When the cop calls it in, though, he says he needs an ambulance at 7th and Broadway. Even assuming Tech Noir was on the corner of Pico and Broadway, that is still about 3/4 of a mile away from 7th and Broadway, so there is no way that was the intersection just outside the alley.
Continuity mistake: After the Endoskeleton emerges from the diesel fire look at his teeth. They're clearly metallic when he stands up and chases after Sarah and Kyle, then when he enters the factory his teeth are white enamel. Then when he's fighting with Kyle they're metal again and finally they turn white after he's blown apart. (01:31:05 - 01:34:20)
Continuity mistake: When the Terminator steps into the house to kill Sarah Connor he walks over the thresh-hold however in the next shot he is outside again. (00:16:15)
Revealing mistake: When Arnie is being pulled under the semi-truck, his foot is caught and the green-colored dummy leg is revealed. It can't be a special effect sock since green screening was not in practice in the early 80s. (01:23:05)
Continuity mistake: At the start of the film when we first see Reese arriving, the drunk homeless guy is holding a bottle in his left hand, then the camera continuously switches between Reese's arrival and the old guy, in these shots, the bottle keeps changing hands from left to right, then back to left. (00:06:40)
Continuity mistake: After the shootout at the disco, there is a car chase. Towards the end of this chase, they turn a corner and Kyle smashes into the police car, veering it off to the right of the screen. If you look closely at Kyle's car as he hits, you can see FIVE shotgun holes in the side of the car. However, a few shots later, Arnie is firing at the same side, but there are only TWO shotgun holes in the side of the car, with Arnie just making the third hole with that shot. (00:47:10)
Continuity mistake: When Kyle is in the police station being interviewed by the psychiatrist, watch where he says the line: "It's just him... and me", it appears different later in the film when the psychiatrist is showing the tape to Sarah. The first time, Kyle has his head turned up and to his left and on the tape, his head is facing straight as he says the line. (00:54:25)
Continuity mistake: Two large railings can be seen curving around the building corners when the cops arrive at the alleyway to pursue Reese. Those railings weren't present in the shot preceding Reese's arrival; the cops pulling up was filmed in a separate alleyway.
Revealing mistake: At the end of the film, at the split second we see the ambulance workers zip up Reese in the bodybag, his right eyelid flinches a bit. (01:39:45)
Continuity mistake: After the Terminator discovers Sarah's mother's address in the little address book of Sarah's, the next shot shows the Terminator leaving his room and going to Sarah's mother's. In that track shot down the hall look at the Terminator's shoes. He's wearing white trainers instead of the black boots he wears for the whole other time in the film. (01:14:40)
Answer: My two cents: The T-800 Terminator does indeed, rip out the page of a phonebook for the address, but remember, he was looking for any and all Sarah Connors, not a specific address. He did not know which Sarah would give birth to John Connor, so by process of elimination he began terminating any woman with the name Sarah Connor. He did plug the first Sarah Connor (a housewife), then went to kill the other Sarah Connors in the phone book.
I already gave that answer, but apparently that's not what the question is asking.
Charles Austin Miller