Also check the ECT sensor. If it has drifted (changed value, a common failure mode), then it tells the cars computer to use a too lean mixture when cold. Thus it runs roughly until it warms.

Mine ECT is a four terminal device (black) mounted on the front of the engine. Here's what the manual says for the ECT's temp (deg C) vs resistance. Pull of the top and use an ohmmeter to measure the resistance between adjacent terminals. Readings should be no more than +/-5% from those below. If so replace the sensor.

Temp(C)-Temp(F)---- Ohms
20 -------- 68 ----------- 2500
30 -------- 86 ----------- 1700
40 ---------104 ---------- 1170
50 ---------122 ----------- 830
60 ---------140 ----------- 600
70 ---------158 ----------- 435
80 ---------176 ----------- 325
90 ---------194 ----------- 245
100---------212 ----------- 185

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Regards . . . . JimF
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'94 S500 Cpe

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