I have a 1994 e320, I had a problem with the idling, it used to rev up and down.... i changed the spark plugs, wires, mass air flow sensor, some vaccuum lines. but now the idle stays high. i tried adjusting it, but it stays the same. in drive its at about 800, and in park it settle at about 1200 or 1300.
it used to be in drive around 500 and park 700.

I read the codes i got:

code 6 in the built in reader
code 8 in pin 8
code 2 in pin 14

any ideas?

I would like to add that during this problem i did play around with the cables adjustments in the engine compartment and at the gas pedal.