First of all tick is simply a one frame. So the higher the FPS - the more ticks you have per second. To show FPS type “Show FPS” in console (~ button).
Packaged build tend to run faster e.g. having more FPS (this is because of several reasons including not having Editor in background and some other debugging stuff, depending on package configuration).
So if you rely some of your logic on tick and FPS is not limited and stable at some value, typically 30 or 60 FPS, your game becomes frame rate dependent.
To avoid such behaviour you have to take into account DeltaTime variable that is given to you in Tick function. DeltaTime equals time that passed since last moment Tick function was called. One of possible ways to deal with your problem is to establish some sort of float variable called Speed (it could be GasDepleetingSpeed for example), then if every tick you want to change your FuelAmount, you should subtract DeltaTime multiplied by GasDepleetingSpeed from FuelAmount.