If you have an airless paint sprayer that is not holding the same pressure it used to while spraying paint there are a few simple checks which can be made to hopefully identify the cause of the pressure loss.
These tests make the assumption that your airless spray machine is already priming and building pressure but then while spraying the pressure is lower than it used to be, or should be.
Tailing when spraying with an airless paint sprayer is a phenomena where two distinct heavier lines of paint appear on either edge of the paint spray pattern. Inside these heavier edge lines there may be no paint or very little paint before the spray pattern reappears and often becomes heavier towards the center.
Tailing with airless paint sprayers can be the result of several different factors or a combination of factors.