Please advice: 91’350SD engine blow up

Need advice on whether it's still worth fixing or junking this car.  (I don't wish to pass on a head-ache to someone else.)  I still love this car for the solid feel and the good overall condition.

Some history:

Bought the car in 1999 and then the engine blew up in 2000 - piston rod went thru bottom of engine, oil drained and hard-stop :-(  After much aggravation, the used car dealer rebuilt the engine in late-2001.  The engine was fine until the blow-up.  After the rebuild, the engine behaved almost normal for about 4 months (but past 3 month waranty), and since then it's not. The symptoms are:

- Car shakes at idle and more shake when in drive (standing still).  The shake is like a rocking of the entire car; overall, less felt-power (sluggish) than before.  Lots of tapping noise from engine.

- Shifts from 1st to 2nd is delayed and then thumps into 2nd.  The time it takes to shift is also unpredictable

- smokes much at idle and then more smoke while accelerating from stand still

btw. from google search, found many owners of this year model have very similar problems

Please advice

Hey folks, is this forum active or not?

C'mon and respond please!

Thanks sleepwalker for your reply.

The shop that re-built the engine is not too interested in identifying the problem, since they will not make more money off of me.

I am taking the car to another mechanic ... let's see what he finds out.

My plan is to replace std things.  Oil change, fuel filter change, transmission oil and filter change, etc.  Then I will ask for a compression test, etc.

btw. I am curious, are you a mercedes mechanic?