So my MC kidnapped someone, and I need him to get away with it (at least until the end of the story). The problem is, he followed his victim around the parking lot not long before he kidnapped him, so the victim's friends were able to see the car. When the cop asks the victim's friends, they tell the cop they saw the victim being stalked and inform him of what kind of car they saw, so when the cop asks the MC what kind of car he drives, he lies. His car is a white Nissan, the MC tells them it is black. This happens a day after the missing person report was filed. I'm not sure if this will work. I'm thinking the cops wouldn't be too suspicious (at least at first) given that it's only been a day since the missing person report was filed, and given that the MC probably wouldn't be first on their list of suspects. Plus, the victim is a nineteen-year-old delinquent who, I think, they wouldn't immediately assume was kidnapped. They'd probably assume he ran away or something first, but at some point, when he still has yet to be found, I'm guessing they'll start looking for suspects, and that's where the issue arises. But I don't know. Should the MC admit to what kind of car he drives? Or would it be better for him to lie and get a new car right away? Is there a more logical route I could take with this?
How exactly do the police connect the MC to the kidnapping? Because you mention he’s not a prime suspect, and without a complete or partial license plate from the witnesses it would be very easy to dismiss the white Nissan as nothing but a coincidence. I don’t think lying about the car’s color or getting a new car right away is necessary, unless there’s some context missing here.
The law varies by state on what determines a missing person. Usually, 24-48 hours. That should give your MC extra time, but if the kidnapping was witnessed and your MC is already a suspect, it wouldn't take the police (nowadays) long to nail him.
Lying about the color of the vehicle would be more of a red flag to the police then admitting the color. Did any of the witnesses see the person driving? If it is a common vehicle unless the driver or license plate was seen it would be hard to prove that the MC did it.
It would take the cop less than 30 seconds to run any registrations the MC has under their name, which would include make, model, and color. Even assuming the MC is driving a car registered to somebody else, it's unlikely this would be something that could be hidden. Even if the cop is a total idiot, which is certainly possible. That's even dumber on the part of your MC. The cops would see the title transfer after the date in question. I don't know... sounds to me like you're going out of your way to create a plot hole here. Unless there's a specific reason why the car has to be witnessed and then reported. Like you're deliberately showing your MC attempting to deceive law enforcement, which is totally fine, but in a narrative sense, seems kind of... cumbersome? Not sure. Would have to know more.
It's easier to just pull up the dmv records. The police don’t ask what kind of car you drive but instead of your whereabouts. If they already knew enough about him to question him in the first place then the police would have obtained a search warrant due to matching the make and model.
Per above, if the victim's friends need to have witnessed something, best it not be something as thoroughly registered and checkable as the car. Maybe the car is parked out of sight, and instead they notice him wearing something distinctive, or overhear him make a memorable comment some time earlier which makes him semi-identifiable, or something? If he's going to lie about something, those things would make more sense and be harder for the cops to check up on.
eyewitness accounts are notoriously unreliable... so you could easily have the vics friends disagree about colour, make, etc
Perhaps you could say that the car does not belong to the MC because it was stolen by the MC and belongs to different owners which would make it more difficult for the cops to track and trace the MC as the owner of this car.
The best thing for you to do is research police guidelines for kidnapping cases. You'll understand better how your plan would/won't work and can amend it. There's loads of kidnapping documentaries detailing the investigation into the kidnapping.