I have a 1993 c4 auto and my reverse only works sometimes when cold when it warms up it only engages with high rpm and still slightly moves all forward gears work perfectly fine the car also sat for 4 years I don’t know the cause if anyone could lead me in the right direction that would be awesome thank you

 

Welcome to the forum.

Check the transmission fluid level when it's hot. You also might consider transmission flush and refill and filter change since it has been setting so long.

 

i checked the fluid while hot and running level is fine I’m gonna flush it and new filter see if it works thanks

 

Let us know how it works out.