Something is very wrong with my game (help needed)

I have been having a lot of trouble recently with beamng for no apparent reason
Here's a list of issues that I have discovered:
-Cars cannot shift out of first gear in arcade or drive modes (manual works some of the time)
-60% of stock cars will not move, they rev up but no matter what I do I can't get the car to move
-Some cars can not stop going full throttle no matter what I do they won't stop
-UI interfaces (especially on scenarios) will sometimes not load, including speedometer and such
There are more issues I have yet to discover about it (yet to find more I haven't explored much yet)

Things I have tried and info on the game
I have the game downloaded directly from steam via an activation key which I bought back in march 2015
It stopped working about a month ago, never bothered to do anything about it until now
I have downloaded a few maps and cars and a lot of them are outdated
I am on windows 10.1, or whatever the latest release is
-I have uninstalled the game via steam uninstallation (which did not change anything including it kept all of my mods for some reason too after I reinstalled)
-Deleted all local files in the steam folder (just deleted all the mods I had, but once I reinstalled the issues
still there just without mods)
-Gone to the uninstall program window and uninstalled it that way (did nothing different from the previous)

If anyone has any questions, can give help or a fix or needs more info just say so!
Thanks for everyone's help!!

 

Thanks for your help, but another even worse issue came up after I did that.
Automatic and arcade transmissions work normally now and, all cars can move along with the other issues I mentioned are working

But now cars cannot pass around 2500 rpm and will not exceed 13 mph no matter what
It affects all cars no matter what it is and I have no more clue how to fix it and I do not understand why they cannot

I deleted the cache and all of the game files and reinstalled on a clean slate just like I did before and it fixed those issues that were there before thankfully.

Again if anyone knows how to help it is much appreciated!
--- Post updated ---
Actually, on a few cars it goes over the 13 mph and 2500 rpm but again the shifting issue is back where it won't go out of first

So on all cars its either it won't go out of first or it won't exceed 13 mph or 2500 rpm

 

Sounds to me that there is something wrong in your controller setup (in case you are using some controller and not keyboard), throttle can have such deadzone that it will not apply full throttle, you could go to controller setup, click your assigned control for throttle and then click revert to get it for original setup, or then just adjust deadzone.



If that does not help, then check combined throttle&brake also.

If it is none of those, then it is bit mystery of why it happens, you sure brake is not on?

From that left menu, that comes when you are in car and press ESC, choose one that says Apps, then click orange '+' in circle that comes to screen, find app that is called "Pedals and Axis" and accept that with blue circle with check mark on it.

If you apply throttle fully, does it show 100% on green bar? Also there should not be red bar at all as it is brake. If you get full 100% throttle and no brake is on, but still can't go faster, then it is something weird and unknown.