trouble code help please

[project 87 5.0]

its an 87. it smells like its running rich as hell, so i pulled test codes. KOER is 41,91. KOEO is 15.i dont know where to begin. it has 2 chamber flowmasters with no x pipe or cats. looks like the person i bought it from had the engine apart. the heads are gold, dont know if they are stock or just painted. thats about all i know about the car. Any leads on where to start will be very helpful. thanks crapola

 

[liljoe07]

91 and 41 are lean codes. Need to go over all the vacuum lines first. Make sure there are no leaks.