Welcome, I am Chris (aka-Moose)
When the cooling fan is staying on, are you using an AC setting? Does the fan remain on while the climate control is off? If the fan does remain on then its possible you have an engine coolant temp sensor reading incorrect which can effect the computers strategy for the way it controls the air fuel ratio. Can you try cleaning the throttle body and some fuel injector cleaner and let me know those results.
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