I'm having a simular problem and have thrown $$$ at it. The entire fuel system has basically been replaced or rebuilt including the ECM, altitude sensor, fuel distributor, regulator, pump, EHA and idle control valve. I'm going to pull the air box tomorrow and check out what's going on under there. I've ordered a new air duct just cuz it's 22 years old. I'm also going to clean up the WOT switch. It shows 18Mohms when it should be infinite. The circuit does close at WOT as it should. I've ruled out anything to do with the fuel system and am now seeking a vacuum leak. Keep me updated on what you find.

gw 85 190e 2.3 8v