It's a struggle getting it to start

This is regarding a 2012 Volkswagon Routan, which I understand to be a Grand Caravan made for Volkswagon.

It's difficult to start. Turn the key and leave it alone as you're supposed to and it will just keep turning over until it gives up after a few seconds.

You have to give it a lot of gas to make it start and it will usually only start on the second try, as though the first time turning it over got some gas into it or something.

This is after two times in the shop.

One morning, apparently the car had been left in DRIVE overnight (I don't know how they managed to get the key out with it in DRIVE, but there it was), and it wouldn't start. It has always seemed to me that the fact that it was left in DRIVE must have something to do with the problem.

We brought it to our mechanic.

The first time the mechanic said it just needed a tune-up and replaced spark plugs and air filter. It started when I picked it up after service, though not as easily as I had been used to. A few hours later it wouldn't start.

The mechanic comes and gets it and this time he replaces the fuel pump.

Now, we can start it with difficulty but there's always the worry that it won't start.

Any ideas?