A ticking noise from your engine is usually caused by a valvetrain problem, of which bad lifters are one of the possible sources. The ticking sound may be caused by the lifter not pumping up correctly or not pumping up at all, resulting in an inadequate amount of oil pressure being supplied to the valvetrain components and causing them to make a knocking sound. This ticking noise is often more noticeable when the engine is idling, but can sometimes be heard even when it’s running at higher speeds.