96 E 300 still cutting out

[mitcheeew]

In the ongoing saga of the dieing diesel, it's now been 3 weeks, & during that time I've had:
1. the K 40 relay replaced (without any improvement,) 2. fuel shut off solenoid replaced (again without any improvement,) 3. lower fuel pump replaced. NO error codes in the meantime. The car turned over & ran for a few days,albeit only sparce errands due to the unreliability, & yesterday while out on an appt 15 miles it died. I left it for a few hours & when I came back it turned over & started - running long enough to bring it back to the dealer,where they are baffled. Meanwhile I'm out close to $1000.00 for assorted labor & "repairs" (not including expenses for tows & being stranded) & back at square one. Most recently the IP developed a leak at the delivery line, but good ol Phil is sending the socket & we'll replace the delivery line O rings & washers. While at the dealer, (who does work with me,) I asked them to get MB involved & start throwing some of their nickels at correctly diagnosing this problem.

Terry - I still have the sporadic clattering from the belt tensioner area after replacing both the tensioner & shock. Told it's from the area below where the bolt goes into the block, but is not fatal. With the other issues it's taken a back seat.

After all this, I'm ready to abandon the car. I'm hoping it will finally be diagnosed & repaired, & with a trade in or sale max of only $5 - 7 K, I am thinking of keeping it for my son's car,considering all the recent maintenance done the past 2 years.Only 139,000 miles,new tires,brakes,plugs,etc. With all the out of state driving I do, I need confidence & reliablity.
I'm having a hard time justifying owning another Benz,or anything German presently. The past week test drove Infiniti M35 (cramped with little storage,)Lexus ES350 (good for napping)& today Acura (RL)-which for my money is quite a car. Teaser thoughts of a used CDI have crept in my mind as a dieseler,but the the cost of ownership & the German electronic's reliabilty & complications have left a soured taste. Any other areas to look at greatly appreciated. (no line leaks,replaced all fuel filters,gotta be some erratic electronic wiring or signal...?)
This forum has been of great help & I would've gotten rid of this boy long ago,had it not been for the details in the DIY dept. I only wish I could lend some insights to others with similar problems.