Probably a sticking and/or inop idle control valve. Pull the idle control valve (ICV) and clean it out with carb cleaner, and check the inlet and outlet hoses; they tend to get brittle and hard with age and can leak. While you have the ICV out, apply 12V to it and make sure it operates - you should hear a loud click. Common problem with these cars.

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93 190E Sportline (RIP) (45K)
92 190E (Xferred most Sportline parts to this body)
88 300CE (71K)

And the Jeeps:
01 2WD Cherokee XJ (35K, Mama's grocery/kid hauler)
91 4WD Comanche (300HP stroker)