Update:

My indy replaced 8 plugs, both caps & rotors, wires, both coils,
all 8 injectors and three days trying to isolate/correct the problem but no luck-
he is referring me to Mercedes. We're both frustrated and disappointed.

Mechanic is excellent and a great guy, no charge for time and parts-
all returned back to stock.

I could really use some expert advise.

thanks in advance!

-andy