Engine 5.0 HO RUNNING RICH

[40sedan]

My 5.0 EFI seems to be running rich exhaust smells heavy any ideas why or what to look for?

 

[General karthief]

Check for codes, that's the best I can do with the limited info such as:
Tuned up recently?
Any modifications?
Just got the stang or been inactive for a long period?
Daily driver and just started running bad?