New Guy With 05' Sprinter Shifter Troubles

I have had my Sprinter for 2 years now and I has been great aside from a few electrical issues. But I do live in humid FL. Recently I had a major overheat with no indications. As a former GM tech, I mean no indications. I didn't realize it until I pulled off of the freeway and noted the terrible stench of burned motor oil. I use Dura Lube at every oil change and that may be what saved this engine so to speak. However I have had over $9500.00 worth of work done at a local import shop and still have issues. All of this work was internal engine work. Now I have a rattle that they claim to be an injector. It doesn't sound like a rod or wrist pin.

Anyway I get the van back and now the engine won't start unless I wiggle the shifter around and or trip the lock tab and get it into neutral. It may or may not start. It left me stranded on the west coast of FL for an hour yesterday until I removed the center console and checked over the mass of electrical in the shifter lever assembly. I was able to unplug the main harness and jump it to start the van to get home. I am wondering if this is a problem with this van or just my luck. I'm going to install an external jumper today so I can drive it and wait for answers as what to do next. I found a shift lever assembly on EBAY but there is no guarantee it will work. Does anyone have any suggestions? Thank you Jim Weller