Question Unity Standard Asset Car (User controlled) can't go forward. I need help for my dream project.

Hello, I'm having a problem in Unity 2019.4 version. I've a standard asset car and AI PathWay cars in my scene. I was working on my project last night, it was all OK. This morning, I can drive backwards, but I can't drive forward. As I understand, front wheels spin backwards with a little force for no reason when I run the game (Without Pressing "W" button. Front wheels leave a skidmark on the ground while driving backwards 4wheel drive car. I can not spin front wheels forward. Back wheels work perfectly , but front wheels stutter forward (appyling backward and forward spin force in the same time I guess) My project suddenly broken. I can share the script . Any ideas, dear developer friends?

Note: My project's aim is: AI cars was stopping when entered a triggerbox. (They reverse and appy handbrake). I could drive my normal car around them and watch the these AIpathwaycars drive and stop in city. Today, my user controlled normal Car thinks it is an AI car and needs to spin front wheels backwards like there is an obstacle infront of it.. I checked unused scripts and tags but no luck. (oh no, why?)

Could it be the Unity program settings itself? Or could it be I played with the car's mass,gravity and torque like huge 999999 numbers and CTRL+Z them? It was working perfectly last night.

EDIT: When I exit the car, car drifting (like on ice) backwards on a plane surface. Gravity settings in Build panel is x = 0 y = -9.81 ,z = 0

EDIT: FIXED IT!. Slıp Limit was 0 . I set it up to 0.3 and fixed.

 

Reading things like this is one of the best parts of helping out here, and look at that, Uncle Freeman figured it all out! SWEET! GO GO GO!