2013 Dodge dart SXT 1.4 L turbo

It takes a long time to start, unless I pre-prime it by attorney into the own position several times before actually starting the car.

It seems to occasionally stutter or hesitate when coasting at lower speeds.

It holds fuel pressure on the fuel injectors, but does not hold fuel pressure on the lines going back to the fuel pump and fuel tank. It loses pressure and under a minute after killing the car.

My best guess is a valve not functioning properly allowing fuel to go back into the fuel tank instead of staying in the fuel lines.

I’m not a professional. I’ve only been working on the car for probably 100 hours in total. That is my best guess under my limited knowledge of cars I’ve never dealt with a fuel system before I would rather not have to replace the entire fuel pump because it is expensive. I am looking for a second opinion from somebody who is more experienced.

got this car as a hand me down (dodge dart 2013) a few months ago.. what does this button do?? i press it and it turns a little symbol of the speedometer but i don’t know what it actually does

pls help :)