Zebra striping is cause by either improper spray / fan pattern, or not over lapping your strokes correctly. If you get a little uneven looking stripes going on. While your painting the entire truck, paint a panel, then a second panel, Then go back to eh first panel and pull the gun way back and do a fast light spray at a 45 degree angle to the panel, and the horizontal pattern you just did. Then spray the third panel, go back and 45 the second panel. Then the fourth panel, then back and 45 the third panel.