Thanks for sharing your valuable find on your problems Mike! My 300E with the 2.6 engine is having the same problem, wiht severe hesitation during and after warm-up. Throttle response has been getting less and less.
Here's my scenrio: I bought the 300E with a blown head gasket, so I had the head rebuilt, cranked up and ran fine. While on my first drive, the fuel gauge was faulty and it ran out of gas, but the fuel pumps pulled rust from the tank and it traveled to the fuel distributor. I cleaned it out, checked for vacum leaks (fixing a few along the way) and now the engine cranks up fine, idles while warming up, and the idles down and dies eventually after obtaining operating temp.
No throttle response at this time, and as I stated that has been progressively worse....now I am wondering if my injectors are clogged with rust, to the point of operation while cold (with cold start valve) and then not operating with warm engine.
I have re-soldered the fuel pump relay, checked throttle position sensor (tps) and took a look at my airflow potentiometer (which has scratches on one surface). This part is hard to locate used, so I can determine if it would make any difference in performance.
Thanks to everyone and their posts on this board, as it has been helpful to determine my engine hesitation problems. Many of the visitors do view this board without joining......me being one of them for about a month or so, but since I'm a 300E owner now, I figured that I should share my experience and knowledge as well. I am considering on starting a 300E car club for the Raleigh-Durham area of North Carolina (and the rest of the state as well).
Thanks again, and I'll be testing and cleaning injectors!