Rough Idle @ Cold Crank (Worse in Cold Weather) + Fluctuating RPM in Drive

[opfor2]

SOLVED - Engine Coolant Temperature Sensor

It's that rare time of year in my state, when the weather dips into cooler temperatures, which gave me the opportunity to test solutions again. Before replacing the ECT sensor, I swapped my MAF sensor for a new one to see if anything changed--nothing of note and the rough idle at cold crank in cold weather continued, so I put my AC Delco MAF sensor back on. Since replacing the ECT sensor, I have had no rough idle from a cold crank in ambient temperatures as cold as 50 degrees (major issues previously started anywhere below 70 degrees).

It's not lost on me that other factors could still be at play--considering I found and fixed a vacuum leak which had little to no *obvious* effect on the original issue--but I waited almost a year to re-focus on this cold crank problem in the prime weather conditions so I'm letting myself enjoy the victory for now.

The Engine Coolant Temperature Sensor is near the power steering pump, correct?

 

[Geotrash]

The Engine Coolant Temperature Sensor is neat the power steering pump, correct?

Yup. Threads into the driver's side cylinder head toward the front.

 

[petethepug]

Victory is sweet. Nice job walking through it in the posts.

 

[opfor2]

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