1995 E300D automatic odd miss
 

I had this over at the E Class section and got nothing. I'm hoping I'll get more insight here.
We are the second owners of this 80,000 mile diesel. About two years ago we were driving home and noticed a slight miss. After getting home, we took the car to our MB dealer and they diagonosed the problem as a leaking fuel line. This seemed to eliminate the problem until recently when the problem has resurfaced. We had been running B10 biodiesel until the price was too outrageous and on our last service 8 months ago had the fuel filter replaced. On our most recent trip, I tried to diagnose this odd miss. It seems to only occur once you've reached 65mph or 2500rpm (which I think are roughly the same). Also this miss goes away if you accelerate from 65. It is only present when you are kinda coasting and have very slight pressure on the gas pedal. When this occurs there is a drop in rpm (as evidenced on the gauge). I put the car in neutral while going 65 and coasting and there is no miss. While in neutral I brought the rpms up to 2500 and don't feel the miss.
In searching, some more info that seems to be non-related. When the fuel level is at half-a-tank or lower, the needle is very jumpy.
Don't know if this is some sort of throttle position sensor or something with the tranny? Any help is appreciated.
Thanks.
John
Eugene, OR