500 engine idle problems

My SL 500 / R129 / May 1995 has idle problems.

Both "Verteiler" (distributors?????) have already been changed, but rev-needle still shivers a bit.

Idle is generally low, around 500 and sometimes it falls, causing the engine to "skat" a bit.

What could that be?

Car has already over 155.000 km

How does the Oil Pressure Guage look at idle?

looks excellent....3 wenn cold, drops to 1-2, on idle around 500. Never below 3 on 2000 rpm.

Isn't that what it should be?
No oil consumption, no fuel smell in oil....

Just these strange ???drop-outs??? for milliseconds...

Maybe the "Wandler" of the automatic transmission?

[-fad]

throwing any DTC codes?

when was the last time it was major serviced? / reviewed for vaccuum leaks?

hope this helps
-fad

Major service? are you kidding?
Munich garages rip you off!!!!

Well, I will try vacuum leak check at the deaslership.

The problem is not bad, you only wait for it, once you are reminded again....Its only bad in gear. Neutral is no problem...
Especiall when many electric user are on (e.g. heated rear shield, lamps, fan, heated seats) and revs drop further marginally it comes up.

I will have the error-codes checked as well.