Lines changing color

Using autoCAD 2009, having problems with my line changing to a lighter color,

when I draw a line going horizontal it would be the color of the layer I put it in, when I draw a vertical line, the lines turns lighter, for example using color 31, horizontal it's the color I assigned it when vertical it turns white, red does the same thing except for when vertical it is pinkish, how do I get it back to be the same horizontal or vertical?

Thanks in advance gang.

Not heard of that before.

Are you drawing a 3D polyline and have line weights turned on? It could just be a display thing due to the 3D perspective/distance.