I have a e350 that me and my wife have converted into a mobile dog grooming unit,went to pick it up from being vinyl wrapped and it wouldn't idle, when you give it gas it runs really rough and was puffing smoke,strong fuel smell. I let it sit for maybe an hour came back and it runs great, I drove it home on problems.I got in it to move it today and same thing,won't idle runs like crap? What should I do first?

 

Items that I would suspect to cause a very rich condition is higher than normal fuel pressure, MAP sensor issue, ECT sensor issue, IAT sensor issue. These would likely be my first suspects based on the description given.

Check your codes and the CM section of the self-test may give a clue to what is wrong.