My 97 c230 starts and runs very rough very first crank of the day. If you start it, rev it, then shut it off a couple of times, it will start and run smoothly about the third or fourth time. Replaced the fuel pressure regulatot, crankshaft sensor, and brushes in alternator. Is my next step the fuel accumulator? I know there is a test to see if it's good but can't seem to find the post that describes it.

So I went to the salvage yard to pull an accumulator. Low and behold there is not one. Just a pump and filter. Can someone verify this so I know I am not just looking in the wrong place.

I don't recall there being one on my 97 C280 or SL320

Have you removed the fuel filter and blew through it to check for a clog?

What condition are the spark plugs?