The guy I’ve used has saved me thousands over the years. But these vans aren’t his specialty.You need to find a real mechanic. Not someone who takes parts off and puts parts on.
You would think a dealership would look a little harder for the problem before saying it’s an engine when it’s a unplugged censor and a wire.
Lastly there was port behind the direct drive last time they need to plug into not sure what it was called