Sputtering/choking/stalling upon start up after sitting less than a week

Having a problem with my 2013 MB Sprinter 2500. This is the second time it has happened in the last few months. After sitting for just six days, I had a real tough time getting it to start and stay running. It would turn over and over and over and then finally catch and run, but would run very clunky and would just sputter out and die after a few seconds. Pressing the gas down did absolutely nothing. Seemed like it wasn't getting proper fuel. Tried again, same thing but was able to get the RPM's up a little by pressing the accelerator. Again, would eventually sputter out and die. 3rd or 4th time I was able to get the RPM's up around 2000-2500 and hold it there until it felt like I was getting proper response to what I was doing with the accelerator. At that point, I let go of the gas, the engine went to idling normally and the van ran totally normal the rest of the weekend. This same exact thing happened a few months ago. At that time we were right close to 30k miles since last fuel filter change so I figured the filter may have been clogged up and that was choking it out, so I changed that. Ran completely normal for months including a 5-week nationwide tour. Then we get back from tour, it sits for 6 days, and the same thing happened. Any thoughts?

Had the same issue recently, but also had a check engine light. P18F100 code was stored and the engine harness on the passenger side fender has a loose connection. No clue if this applies to you or not. Was covered under warranty and I didn't inquire further. I only had a no-start once, though (after sitting for a few days). Once started, it would run with some gas applied, and then smooth out and idle fine. It would also chug occasionally when in gear and moving out of a parking spot. The chugging came first, then a check engine light a thousand miles later, and then the no start about 2K miles after the chugging started. We were on a trip, so this is in the span of a week.

Eh, there's no check engine light on associated with the problem.. Thank you though! Anyone else have an idea?