HTML Form doesn't seem to be reaching my Query [closed]

I'm making a little website, just for local use, and have a query that adds some data to my database. I've done this before and just used the same method, because that works.But for some reason the HTML form doesnt seem to reach my query. I have looked it over and tried a lot of stuff, but i just cant figure it out. I know i'm looking over something, but idk what. Please help.

relevant code is below:

$carID = $_POST['carID'];
$post2 = 0;

if($_SERVER["REQUEST_METHOD"] == "POST" and $post2 == 1){
$displacement = $_POST['displacement'];
$cylinder_layout = $_POST['cylinder_layout'];
$cylinder_count = $_POST['cylinder_count'];
$horsepower = $_POST['horsepower'];
$gears = $_POST['gears'];
$trans_type = $_POST['trans_type'];
$engine_layout = $_POST['engine_layout'];
$mileage = $_POST['mileage'];
$pp = $_POST['pp'];
$car_type = $_POST['car_type'];
$stock = $_POST['stock'];

$insertquery = "INSERT INTO specs (displacement, cylinder_layout, cylinder_count, horsepower, gears, trans_type, engine_layout, mileage, pp, car_type, carID, stock)
VALUES ('$displacement', '$cylinder_layout', '$cylinder_count', '$horsepower', '$gears', '$trans_type', '$engine_layout', '$mileage', '$pp', '$car_type', '$carID', '$stock')";
$insertresult = $conn->query($insertquery);
header("location:list_full.php");
}

the HTML form:

<form action='list_full.php' method="POST">
                    <label>Displacement</label>
                    <input type='text' name='displacement' class='form-control'/>
                    <br>
                    <label>Cylinder Layout</label>
                    <input type='text' name='cylinder_layout' class='form-control'/>
                    <br>
                    <label>cylinder_count</label>
                    <input type='text' name='cylinder_count' class='form-control'/>
                    <br>
                    <label>Horsepower</label>
                    <input type='text' name='horsepower' class='form-control'/>
                    <br>
                    <label>Gears</label>
                    <input type='text' name='gears' class='form-control'/>
                    <br>
                    <label>Transmission</label>
                    <input type='text' name='trans_type' class='form-control'/>
                    <br>
                    <label>Engine Layout</label>
                    <input type='text' name='engine_layout' class='form-control'/>
                    <br>
                    <label>Mileage</label>
                    <input type='text' name='mileage' class='form-control'/>
                    <br>
                    <label>PP Rating</label>
                    <input type='text' name='pp' class='form-control'/>
                    <br>
                    <label>Car Type</label>
                    <input type='text' name='car_type' class='form-control'/>
                    <br>
                    <label>Stock</label>
                    <input type='text' name='stock' class='form-control'/>
                    <br>
                    <label>Car ID</label>
                    <input type='text' name='carID' value='<?php echo $carID ?>' class='form-control'/>
                    <br>
                    <?php
                    $post2 = 1;
                    ?>
                    <button type="submit" value="Submit" class="btn btn-primary">Submit</button>
                </form>

Here is also a screenshot of my database, specifically the table the form should insert the data into (the data in there is just inserted within phpmyadmin, not using the query): https://imgur.com/a/92z52xB

source https://stackoverflow.com/questions/73666555/html-form-doesnt-seem-to-be-reaching-my-query