Propane ignitor for Charcoal Grill pops

I have a Weber Performer charcoal grill that uses a propane ignitor. The grill is quite old and uses the small propane tank (15 lb full). The grill still works great and the ignitor has worked very well for many years. But recently, it has become somewhat difficult to light, and once lit, it pops about every 3 to 5 seconds. It will work even though it is popping. I have cleaned the burner tube and the opening where the fire for igniting is. I have also cleaned the orifice and surrounding area. I also changed the propane tank. All to no avail. Can you suggest what may be the problem and more importantly what might be a solution?

 

I haven't used a charcoal grill in many years and was not aware of propane ignition.
Trying to figure out why you would use propane to light charcoal.

Your problems sounds like a plugged orifice which is a very common outdoor problem.