The connector for attaching the regulator to a disposable propane cylinder has a sintered bronze filter in the tip of the brass probe tube that is prone to clogging, or the bronze pellets get mashed down over time, restricting gas flow, and this will cause a portable grill or camp stove to perform poorly. The filter is so fine that it takes very good eyesight and bright light to see that it isn't solid metal, or use of a strong magnifying lens. The best solution is to buy a new Coleman regulator assembly. If you are unable to get a new regulator assembly and have the skills and the tools, you can try drilling a very small hole on the side of the probe tube with a #60 drill bit, just below the bronze filter, but near enough the end of the tube so that the hole will be past the plastic seal when the disposable cylinder is fully screwed into place. You should avoid drilling directly into the end of the probe tube, as the end of it is used to depress the Schrader valve in the disposable cylinder to allow gas to flow. A #60 wire gauge drill bit is only 0.040 inch (1.016 mm) in diameter, but makes a hole large enough to supply sufficient gas to a portable grill or a dual-burner camp stove. If you choose to perform this work, the probe should be unscrewed from the regulator body and the Schrader valve core in the probe tube should be removed before drilling. Be sure to clean all brass and bronze particles out of the probe tube before re-installing the Schrader valve core and the screwing the probe into the regulator. Use a removable-grade thread locking compound to secure the probe in the regulator body and don't over-tighten it, so as not to crush the rubber gasket. Allow the thread locking compound to cure for several hours before attempting to use the regulator. Keep in mind that this modification increases the likelihood of dirt getting into the needle valves and jets of your stove or grill, which can cause maintenance problems in the future.