As a follow up to this post, I have since found out that the mechanic did not change any hoses that I can find!
I did find some sealant around one of hoses going from the idle control valve. I have forgotten where the hose goes but it's the one on the right as you face the ICV from the front of the car.
I won't be going back to the mechanic. They told me the hose was in the starting circuit and was so old that it fell apart. Little did that mechanic know that I replaced the hose about two months prior so I know it was new. He slathered some sort of grey sealer around the hose attaching to the ICV. Now it's going to be that much tougher to clean it out.
So, if your 300E dies and won't restart, pop the air cleaner assembly off and inspect the hoses to and from the ICV.
Leanring more all the time. Too bad it can be expensive.