Do you have a CEL (check engine light)?
Some causes of idle problems are a bad IAC (idle air control) valve, bad O2 sensors, gunked up throttle body, or vacuum leak.
Also, since I see that you are in Chicago, cold weather sometimes effects the condensation level of gasoline. You might want to put a bottle of HEET (or something similar) in your gas to dry it up from any condensation.
96 Contour SE
Duratec V6 24-valve 2.5L ATX
108,000 mi.
Replaced: crankshaft w/ DMD, EGR valve (clogged), EVR, DPFE, PCV valve, evap emissions hose & tube (cracked), window regulator (broken), LH & RH PCV tubes, UIM gasket (leak), ignition coil
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