I had similar problem on my 1988 560SL. Problem was the engine temperature sensor that feeds the fuel injection computer. This sensor is located in the intake manifold, front of engine on the driver side just under the front edge of the air cleaner. The sensor has a green top and two wires attached. You must remove air cleaner to access.
The problem is obviously engine temperature-related. I think you replaced way too much stuff chasing this problem. Let logic and ALLDATA be your guide.

Rough idle may be a separate problem, probably a vacuum leak. There is an intake manifold vacuum outlet on the rear of the engine on the passenger side. My connecting rubber hose was rotted/split there. Replaced and idles smoothly. The clue to that hose being bad is your "economy" indicator. If it does not work or does not go full range, that vacuum connection needs attention. The connection may be found by tracing the vacuum tuble that runs from a 4-way vacuum connector at the driver's side firewall and across the top of the firewall into the intake manifold vacuum outlet.