What plugs are being used by everyone?
I installed platinum quads in my '91 300E thing nothing but the best for this baby .... and then I started having all kinds of weird starting and running problems.
I found one of the spark plug wires to be bad and replaced it, I then pulled the platinums and installed the standard recommended (inexpensive) single electrode plugs (per the owner's manual) the car has run exceptionally well since.
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)