Sounds exactly like the EHA is the culprit as I have the same experience when I first got my 260E. You can try giving it a turn rich and see what happens. Two bolts and its in your hand (air assembly off)...Then undo the screw on the back and use an allen key to turn clockwise...Based on what you are saying I'd go for a full 180 turn. Close it back and go for a spin. If it seems more responsive you got the culprit.

Of course it could be bad injectors, but this test is free above. If you see no difference, CHANGE IT BACK!!! Make sure you record how far you turned it. Clockwise = richer, Anticlockwise = lean.

180k is a lot of general wear on the fuel system. Have you also tried seafoaming her? Might be a good one as well for a general item to do.

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k