Chris the best thing for you to do is to hit every one of those butt connectors and clean each and every one of them, then re-seat them. There aren't as many as you'd think. The biggest ball of them is under the hood above the starter, and behind the fuse box.
I've never tried to crimp any of mine. Any time they've been loose, it's because they weren't pushed into the other end of the connector all the way. I always seat mine with a needle nose pliers, being careful not to smash the insulation around the wire. I find they can be quite stubborn and tricky to seat with just finger pressure, and that is probably what the previous owner did to your car. They should almost 'snap' a little when they are pushed in all the way. Try it with a pliers, and you'll see what I mean.