car doesn't always shift out of its final gear

Before someone tells you the tranny is shot, you can recode the transmission control module for timing shifts. This is a project for a mid level mechanic, if you are not familiar I wouldn't attempt it yourself. Run the car by a reputable shop and ask them to look at the control module. If its functioning properly... unfortunately the tranny is going out. Best of luck!

So will a control module also help when first and second is okay but when it comes to third gear it looses its power until it slowly gains power again and also the reverse hesitates into gear takes like 2 or 3 seconds to shift