Changed coolant temp sensor, then I had a rough idle especially on cold starts...???

[Shtiv]

Changed out my coolant temp sensor on my 2002 Yukon Denali, then immediately had a very violently rough idle on cold start? Seems weird to me and wonder if something else happened. Looking to see if this issue makes any sense to anyone? Thanks for any help.

 

[Tonyrodz]

Changed out my coolant temp sensor on my 2002 Yukon Denali, then immediately had a very violently rough idle on cold start? Seems weird to me and wonder if something else happened. Looking to see if this issue makes any sense to anyone? Thanks for any help.

Have a cel?

 

[Merc1973]

What brand sensor. If aftermarket it might be giving computer faulty data... stick with OEM

 

[OR VietVet]

Yea, either a crappy sensor, stick with OE parts, or maybe a pin in the connector is damaged or backed out when reinstalled connector. Plus, like @Tonyrodz said, CEL?