Trust me on this.
It seems to be a reasonably interesting story, your voice is just fine. That much I can tell from what you've given. But the ending seems very weak, although since these are only three very small excerpts, it's hard to know.
I'm dithering about suggesting you're telling too much, not directly showing enough, but since the story is a looking back in hindsight, that may actually work. Again, what you've posted, simply isn't enough.
I actually did a little reading out loud in the middle of the car thing, because at first glance I thought it was far too wordy. But it read aloud beautifully, which is wonderful. I would like to see more of the two of you driving across the Detroit metro area. Make sure that those who know that city, and those who don't know it, all get a clear picture of the drive.
My essential advice is going to be get a grip on paragraphing. Put the story aside for at least a week, then go back to it and work on editing. If you possibly can, take a creative writing class at your local university or find a group to workshop with. If those things aren't possible, don't sweat it. Just keep on writing.
I also wonder if in the end you don't actually have the bones of a novel. It looks like a lot of ground, emotional and physical, has been covered, and if you take this story, then flesh it out in full detail, voila! A novel.
Also, and this won't exactly apply to what you cut and paste to this forum, but make sure that when you're actually typing it out on your computer, you are double spacing.